This pilot study reports the development of a coding system for quantitative analysis of paintings produced by psychiatric patients. Color, color intensity, quality of line, space covered, and subjectively judged emotional tone as characteristics of paintings were recorded in each section of a grid superimposed over the picture. A sample of 39 psychiatric patients were classified into 4 groups using ICD-10 criteria: depression, psychosis, brain injury, and drug abuse. Six independent raters achieved excellent reliability across all scales on each of eight pictures. Analysis of variance results show that each diagnostic group differed on 4 of 13 variables: yellow, orange, color intensity, and line (p< .02). The prospects for further research are discussed.