For a prospecdive study of lead exposure and early development, we recruited pregnant women from a lead smelter town and from an un town in Yugoslavia and followed their children through 7 years ofage. In this paper we consider associations between lifetime lead exosure, estimated by the area under the blood lead (BPb) versus time curve (AUC7), and intelligence, with particular concern for identiying lead's behavioral signature. The Wechsler Intelligence Scales for Children-Version III (WISC-III) was administered to 309 7-year-old children, 261 of whom had complete data on intllince, blood lead, and relevant sociodemographic covariates [i.e., Home Observation for the Measurement of the Environment (HOME), birth weight, gender, sibship size, and maternal age, ethnicity, intelligence, and education]. These showed anticipated associations with 7-year intelligence, eplaning 4147% of the variance in Full Scale, Performance, and Verbal IQ. Before covarate adjustment, AUC7 was unrelated to intelligece; after adjustment, AUC7 explained a s4iflcant 2.8%-4.2% of the variace in IQ. After adjustment, a change in lifitime BPb from 10 to 30 pg/dl related to an estimated decrease of 4.3 Full Scale IQpoints; estimated decreases for Verbal and Performance IQ were 3.4 and 4.5 points, respeely. AUC7 was significantly and negtily related to three WISC-III factor scores: -Freedom from Distactibility, Perceptual Organization, and Verbal Comprehension; the association with Perceptual Organization was the strongest. Consistent with previous studies, the IQ/lead association is small relative to more powerful social factors. Findings offer suppor for lead's behavioral siture: perceptual-motor skils are significantly more sensitive to leud exposure than are the language-related aspects of intelligence. Key swrd:. child development, intelligence, lead, perceptual motor functioning, WISC-IlI. Environ Heakh Perspect 105:956-962 (1997). hp//ehis.nie/inih.gov