This database contains images used for training a fully convolutional neural network for the semantic segmentation of clouds in images from the Sentinel-2 Level 2A Satellite. The images refer to the RGB composition (bands 4, 3, and 2). After that, each band was converted to a byte type (0-255). The images are still divided into three main sets: training, validation and testing: Training dataset: it contains 1.160 GeoTIFF images with 512x512 pixels and associated PNG masks (clouds indicated in white and background in black color). Validation dataset: it contains 100 GeoTIFF images with 512x512 pixels and associated PNG masks used for validation step. Test dataset: it contains 100 GeoTIFF images 512x512 pixels for testing.