Several smoothing methods for binary contours based on chain codes have already been proposed in the literature. Chain codes are very popular approaches for representing the external and internal boundaries of binary contours. RLE (run-length encoding) is also a compact representation of a binary image. Due to simplicity and popularity of the RLE representation, a simple smoothing method for the RLE data is proposed in this paper. The new method smoothes horizontal, vertical, and diagonal out-spikes of the foreground regions with only one-pixel-width on their outer and inner binary contours.