diff --git a/R-package/R/predict.xgb.Booster.R b/R-package/R/predict.xgb.Booster.R
index 49f1ad4f0..1e458e708 100644
--- a/R-package/R/predict.xgb.Booster.R
+++ b/R-package/R/predict.xgb.Booster.R
@@ -7,8 +7,8 @@ setClass("xgb.Booster")
 #' @param object Object of class "xgb.Boost"
 #' @param newdata takes \code{matrix}, \code{dgCMatrix}, local data file or 
 #'   \code{xgb.DMatrix}. 
-#' @param missing Missing is only used when input is dense matrix, pick a float
-#     value that represents missing value. Sometime a data use 0 or other extreme value to represents missing values.
+#' @param missing Missing is only used when input is dense matrix, pick a float 
+#'     value that represents missing value. Sometime a data use 0 or other extreme value to represents missing values.
 #' @param outputmargin whether the prediction should be shown in the original
 #'   value of sum of functions, when outputmargin=TRUE, the prediction is 
 #'   untransformed margin value. In logistic regression, outputmargin=T will
diff --git a/R-package/R/xgb.DMatrix.R b/R-package/R/xgb.DMatrix.R
index b7a5a9897..8c3ea80bc 100644
--- a/R-package/R/xgb.DMatrix.R
+++ b/R-package/R/xgb.DMatrix.R
@@ -6,7 +6,7 @@
 #'   indicating the data file.
 #' @param info a list of information of the xgb.DMatrix object
 #' @param missing Missing is only used when input is dense matrix, pick a float
-#     value that represents missing value. Sometime a data use 0 or other extreme value to represents missing values.
+#'     value that represents missing value. Sometime a data use 0 or other extreme value to represents missing values.
 #
 #' @param ... other information to pass to \code{info}.
 #' 
diff --git a/R-package/R/xgb.cv.R b/R-package/R/xgb.cv.R
index 2129b418a..ed088df52 100644
--- a/R-package/R/xgb.cv.R
+++ b/R-package/R/xgb.cv.R
@@ -32,7 +32,7 @@
 #' @param nfold number of folds used
 #' @param label option field, when data is Matrix
 #' @param missing Missing is only used when input is dense matrix, pick a float
-#     value that represents missing value. Sometime a data use 0 or other extreme value to represents missing values.
+#'     value that represents missing value. Sometime a data use 0 or other extreme value to represents missing values.
 #' @param prediction A logical value indicating whether to return the prediction vector.
 #' @param showsd \code{boolean}, whether show standard deviation of cross validation
 #' @param metrics, list of evaluation metrics to be used in corss validation,
@@ -134,4 +134,4 @@ xgb.cv <- function(params=list(), data, nrounds, nfold, label = NULL, missing =
 # Avoid error messages during CRAN check.
 # The reason is that these variables are never declared
 # They are mainly column names inferred by Data.table...
-globalVariables(".")
\ No newline at end of file
+globalVariables(".")
diff --git a/R-package/R/xgboost.R b/R-package/R/xgboost.R
index 39e047e8e..c72c4d5b0 100644
--- a/R-package/R/xgboost.R
+++ b/R-package/R/xgboost.R
@@ -5,7 +5,7 @@
 #' @param data takes \code{matrix}, \code{dgCMatrix}, local data file or 
 #'   \code{xgb.DMatrix}. 
 #' @param label the response variable. User should not set this field,
-#    if data is local data file or  \code{xgb.DMatrix}. 
+#'    if data is local data file or  \code{xgb.DMatrix}. 
 #' @param params the list of parameters. Commonly used ones are:
 #' \itemize{
 #'   \item \code{objective} objective function, common ones are
@@ -24,7 +24,8 @@
 #' @param verbose If 0, xgboost will stay silent. If 1, xgboost will print 
 #'   information of performance. If 2, xgboost will print information of both
 #'   performance and construction progress information
-#' @param missing Missing is only used when input is dense matrix, pick a float value that represents missing value. Sometime a data use 0 or other extreme value to represents missing values.
+#' @param missing Missing is only used when input is dense matrix, pick a float 
+#'     value that represents missing value. Sometime a data use 0 or other extreme value to represents missing values.
 #' @param ... other parameters to pass to \code{params}.
 #' 
 #' @details 
diff --git a/R-package/man/predict-xgb.Booster-method.Rd b/R-package/man/predict-xgb.Booster-method.Rd
index 66cdfc36c..204a8167f 100644
--- a/R-package/man/predict-xgb.Booster-method.Rd
+++ b/R-package/man/predict-xgb.Booster-method.Rd
@@ -13,7 +13,8 @@
 \item{newdata}{takes \code{matrix}, \code{dgCMatrix}, local data file or
 \code{xgb.DMatrix}.}
 
-\item{missing}{Missing is only used when input is dense matrix, pick a float}
+\item{missing}{Missing is only used when input is dense matrix, pick a float
+value that represents missing value. Sometime a data use 0 or other extreme value to represents missing values.}
 
 \item{outputmargin}{whether the prediction should be shown in the original
 value of sum of functions, when outputmargin=TRUE, the prediction is
diff --git a/R-package/man/xgb.DMatrix.Rd b/R-package/man/xgb.DMatrix.Rd
index 227fb515f..31efde687 100644
--- a/R-package/man/xgb.DMatrix.Rd
+++ b/R-package/man/xgb.DMatrix.Rd
@@ -11,7 +11,8 @@ indicating the data file.}
 
 \item{info}{a list of information of the xgb.DMatrix object}
 
-\item{missing}{Missing is only used when input is dense matrix, pick a float}
+\item{missing}{Missing is only used when input is dense matrix, pick a float
+value that represents missing value. Sometime a data use 0 or other extreme value to represents missing values.}
 
 \item{...}{other information to pass to \code{info}.}
 }
diff --git a/R-package/man/xgb.cv.Rd b/R-package/man/xgb.cv.Rd
index 12aaf9bf1..149ec392f 100644
--- a/R-package/man/xgb.cv.Rd
+++ b/R-package/man/xgb.cv.Rd
@@ -31,7 +31,8 @@ xgb.cv(params = list(), data, nrounds, nfold, label = NULL,
 
 \item{label}{option field, when data is Matrix}
 
-\item{missing}{Missing is only used when input is dense matrix, pick a float}
+\item{missing}{Missing is only used when input is dense matrix, pick a float
+value that represents missing value. Sometime a data use 0 or other extreme value to represents missing values.}
 
 \item{prediction}{A logical value indicating whether to return the prediction vector.}
 
diff --git a/R-package/man/xgboost.Rd b/R-package/man/xgboost.Rd
index dec97f239..035eec9e7 100644
--- a/R-package/man/xgboost.Rd
+++ b/R-package/man/xgboost.Rd
@@ -10,7 +10,8 @@ xgboost(data = NULL, label = NULL, missing = NULL, params = list(),
 \item{data}{takes \code{matrix}, \code{dgCMatrix}, local data file or
 \code{xgb.DMatrix}.}
 
-\item{label}{the response variable. User should not set this field,}
+\item{label}{the response variable. User should not set this field,
+if data is local data file or  \code{xgb.DMatrix}.}
 
 \item{params}{the list of parameters. Commonly used ones are:
 \itemize{
@@ -33,7 +34,8 @@ xgboost(data = NULL, label = NULL, missing = NULL, params = list(),
 information of performance. If 2, xgboost will print information of both
 performance and construction progress information}
 
-\item{missing}{Missing is only used when input is dense matrix, pick a float value that represents missing value. Sometime a data use 0 or other extreme value to represents missing values.}
+\item{missing}{Missing is only used when input is dense matrix, pick a float
+value that represents missing value. Sometime a data use 0 or other extreme value to represents missing values.}
 
 \item{...}{other parameters to pass to \code{params}.}
 }