Cotmap is a plant mapping technique which assists with the collection, calculation, and analyses of plant structure, boll distribution and boll retention variables of cotton. Plant structure variables include description of main stem nodes, branches, and height. Detailed information for the prime fruiting sites of the cotton plant is analyzed while bolls at other specified positions are examined accumulatively. A description of the mapping procedure and documentation of the program is presented. This technique is useful for distinguishing differences among genotypes and the effects of various treatments on cotton.