One hundred firms were chosen by random sampling in order to survey the conditions of illumination in the small industry of Finland. The illumination of each worker's (N = 1181) work level was measured with a cosine corrigated luxmeter. Blend, the evenness of illumination, and the location of the light source were additional criteria used to evaluate illumination. Of the workers, 23% had moderately poor and 20% had poor illumination. Great differences in the prevalence of poor illumination were found for different industries and occupations. Work requiring precision was illuminated better than coarser work. The results of this study indicate that improved illumination in small industry would prevent undue work load and increase productivity.