An independent replication of a previous study (Schroeder et al., 1985) of the effects of interactive social environmental factors on the relationship of lead and Stanford-Binet IQ was performed on 75 of 80 low-Socioeconomic status black children screened by county health departments in North Carolina. Children's mean blood lead (PbB) level was 20.8 micrograms/d1 (range 6.3 to 47.4). Multivariate regression analyses showed no significant interactions between PbB and age, sex, maternal IQ, Caldwell home environment score, or SES (Hollingshead Two-Factor Index). There was a highly significant negative relationship between both mean and maximum PbB levels with IQ, p< .002: that is, IQ decreased linearly as PbB increased. The most accurate and precise regression model included lead, maternal IQ, home environment, and gender. (Copyright (c) 1986 American Association on Mental Deficiency.)