MASQOTGrid is a simple graphical application for gridding of two-channel microarray data. It handles arbitrary-sized grids with basic interactive alterations such as stretching, rotating and auto-mated local adjustment of the grid. This helps to ensure that spot coordinates are correctly identified prior to segmentation. To set up the grid, MASQOTGrid handles import of GenePix Array Layout (GAL) or GenePix Result (GPR) files. Support for additional formats may be added in the future, depending on user demands.