diff --git a/R/ranger.R b/R/ranger.R
index c33da627..6d56d4d4 100644
--- a/R/ranger.R
+++ b/R/ranger.R
@@ -659,6 +659,9 @@ ranger <- function(formula = NULL, data = NULL, num.trees = 500, mtry = NULL,
     if (length(inbag) != num.trees) {
       stop("Error: Size of inbag list not equal to number of trees.")
     }
+    if (any(sapply(inbag, length) != nrow(x))) {
+      stop("Error: Size of at least one element in inbag not equal to number of samples.")
+    }
   } else {
     stop("Error: Invalid inbag, expects list of vectors of size num.trees.")
   }