In order to study the signal-sight reading learning and the factor structure of intellectual abilities at preliterate moderate and severe levels of mental retardation (IQ 25-55), a test battery of items covering six hypothetical factors was constructed and administered to 80 preliterate mentally retarded subjects. The four factors extracted through factor analysis were called perceptual, memory-quantitative, psychomotor, and verbal-general. Analysis of the relationship between a learning variable (social sight learning) and intellectual factors showed that the perceptual factor had the highest positive correlation with the learning variable. Next highest correlations were found in the memory-quantitative and verbal factors. It was concluded that the findings agreed with those of previous factorial studies in showing that the one-dimensional IQ description of intelligence is not adequate to characterize the intellectual ability structure even on preliterate levels in the mentally retarded, since it is possible even on this level to secure a differentiated factor structure. (Author/KW)