This paper deals with matrix transformations preserving the meanconvexity of sequences. The main result gives the necessary and suf-
ficient conditions for a non-negative matrix A to preserve the meanconvexity of sequences. Also, we state a property for such a matrix
A to map a non-mean-convex sequence into a mean-convex sequence.
Then we consider the case where a matrix A maps a mean-convex sequence into a convex sequence. Further, we discuss the mappings of
mean-convex sequences by the Abel matrix and Borel matrix.