Purpose: The objective of this study was to determine the effect of total sugar intake by pregnant adolescents frcm low-income families on infant birth weight and small-for-gestational-age (SGA) infants.Methods: The study sample consisted of 337 adolescents, enrolled in a county-wide demonstration project in Camden, New Jersey, who delivered live, singleton newborns. The adolescents were divided into two groups at the 90th percentile for the study sample total sugar intake (206 g): high-sugar intake (≥ 206 g, n = 34) and low-sugar intake group (< 206 g, n = 303).Results: The sample was 46% black, 30% white, and 24% Hispanic. The sample gestational age and birth weight (mean ± SD) were 39 ± 3 weeks and 3189 ± 666 g, respectively. After adjusting for energy intake, the high-compared with the low-sugar intake group was more likely to consume higher total sugar and carbohydrate but lower protein and fat. Likewise, the high-compared to the low-sugar intake group consumed significantly more calcium and magnesium. After adjusting for possible confounding variables such as maternal age, ethnicity, marital status, parity, smoking, net weight gain, body mass index, energy intake, and gestational age at birth, adolescents on high-compared to low-sugar diets gave birth to infants weighing 215 ± 104 g less (p = 0.04). The adjusted odds ratios were 3.41 (95% confidence interval, 1.14 to 10.23) for delivering a SGA infant among adolescents with high-compared with low-sugar intakes.Conclusions: Low-income adolescents consuming high-sugar diets are at increased risk for delivering lower birth weight and SGA infants.