diff --git a/R/predict.R b/R/predict.R
index 7ed7b0e5..d11c453e 100644
--- a/R/predict.R
+++ b/R/predict.R
@@ -48,7 +48,7 @@
 ##' @param type Type of prediction. One of 'response', 'se', 'terminalNodes', 'quantiles' with default 'response'. See below for details.
 ##' @param se.method Method to compute standard errors. One of 'jack', 'infjack' with default 'infjack'. Only applicable if type = 'se'. See below for details.
 ##' @param seed Random seed. Default is \code{NULL}, which generates the seed from \code{R}. Set to \code{0} to ignore the \code{R} seed. The seed is used in case of ties in classification mode.
-##' @param num.threads Number of threads. Default is 2 if not set by options/environment variables (see below).
+##' @param num.threads Number of threads. Use 0 for all available cores. Default is 2 if not set by options/environment variables (see below).
 ##' @param verbose Verbose output on or off.
 ##' @param inbag.counts Number of times the observations are in-bag in the trees.
 ##' @param ... further arguments passed to or from other methods.
@@ -450,7 +450,7 @@ predict.ranger.forest <- function(object, data, predict.all = FALSE,
 ##' @param quantiles Vector of quantiles for quantile prediction. Set \code{type = 'quantiles'} to use.
 ##' @param what User specified function for quantile prediction used instead of \code{quantile}. Must return numeric vector, see examples.
 ##' @param seed Random seed. Default is \code{NULL}, which generates the seed from \code{R}. Set to \code{0} to ignore the \code{R} seed. The seed is used in case of ties in classification mode.
-##' @param num.threads Number of threads. Default is 2 if not set by options/environment variables (see below).
+##' @param num.threads Number of threads. Use 0 for all available cores. Default is 2 if not set by options/environment variables (see below).
 ##' @param verbose Verbose output on or off.
 ##' @param ... further arguments passed to or from other methods.
 ##' @return Object of class \code{ranger.prediction} with elements
diff --git a/R/ranger.R b/R/ranger.R
index 028616c2..6fa95ddf 100644
--- a/R/ranger.R
+++ b/R/ranger.R
@@ -133,7 +133,7 @@
 ##' @param quantreg Prepare quantile prediction as in quantile regression forests (Meinshausen 2006). Regression only. Set \code{keep.inbag = TRUE} to prepare out-of-bag quantile prediction.
 ##' @param time.interest Time points of interest (survival only). Can be \code{NULL} (default, use all observed time points), a vector of time points or a single number to use as many time points (grid over observed time points).
 ##' @param oob.error Compute OOB prediction error. Set to \code{FALSE} to save computation time, e.g. for large survival forests.
-##' @param num.threads Number of threads. Default is 2 if not set by options/environment variables (see below).
+##' @param num.threads Number of threads. Use 0 for all available cores. Default is 2 if not set by options/environment variables (see below).
 ##' @param save.memory Use memory saving (but slower) splitting mode. No effect for survival and GWAS data. Warning: This option slows down the tree growing, use only if you encounter memory problems.
 ##' @param verbose Show computation status and estimated runtime.
 ##' @param node.stats Save node statistics. Set to \code{TRUE} to save prediction, number of observations and split statistics for each node.
diff --git a/man/predict.ranger.Rd b/man/predict.ranger.Rd
index 1fce859f..2f9c63ac 100644
--- a/man/predict.ranger.Rd
+++ b/man/predict.ranger.Rd
@@ -38,7 +38,7 @@
 
 \item{seed}{Random seed. Default is \code{NULL}, which generates the seed from \code{R}. Set to \code{0} to ignore the \code{R} seed. The seed is used in case of ties in classification mode.}
 
-\item{num.threads}{Number of threads. Default is 2 if not set by options/environment variables (see below).}
+\item{num.threads}{Number of threads. Use 0 for all available cores. Default is 2 if not set by options/environment variables (see below).}
 
 \item{verbose}{Verbose output on or off.}
 
diff --git a/man/predict.ranger.forest.Rd b/man/predict.ranger.forest.Rd
index 0331fc4b..805effda 100644
--- a/man/predict.ranger.forest.Rd
+++ b/man/predict.ranger.forest.Rd
@@ -33,7 +33,7 @@
 
 \item{seed}{Random seed. Default is \code{NULL}, which generates the seed from \code{R}. Set to \code{0} to ignore the \code{R} seed. The seed is used in case of ties in classification mode.}
 
-\item{num.threads}{Number of threads. Default is 2 if not set by options/environment variables (see below).}
+\item{num.threads}{Number of threads. Use 0 for all available cores. Default is 2 if not set by options/environment variables (see below).}
 
 \item{verbose}{Verbose output on or off.}
 
diff --git a/man/ranger.Rd b/man/ranger.Rd
index 9e519c16..4b1f61fe 100644
--- a/man/ranger.Rd
+++ b/man/ranger.Rd
@@ -112,7 +112,7 @@ ranger(
 
 \item{oob.error}{Compute OOB prediction error. Set to \code{FALSE} to save computation time, e.g. for large survival forests.}
 
-\item{num.threads}{Number of threads. Default is 2 if not set by options/environment variables (see below).}
+\item{num.threads}{Number of threads. Use 0 for all available cores. Default is 2 if not set by options/environment variables (see below).}
 
 \item{save.memory}{Use memory saving (but slower) splitting mode. No effect for survival and GWAS data. Warning: This option slows down the tree growing, use only if you encounter memory problems.}