In Pakistan, there is limited evidence for the levels and relationship of 25 (OH) Vitamin D (25(OH)D) status in pregnant women and their newborns, while the association between maternal 25(OH)D and newborn anthropometric measurements remains unexplored. Sociodemographic data were collected from 213 pregnant mothers during their visit to a tertiary care hospital at the time of childbirth. Anthropometric measurements were performed on all mothers and their newborns and blood samples collected from both for 25(OH)D levels. Participants were classified into two groups according to their 25(OH)D status: sufficient (25(OH)D ≥50 nmol L−1) and deficient (25(OH)D <50 nmol L−1). Simple and multiple regression models were used for analysis. Among 213 pregnant women, prevalence of 25(OH)D deficiency was 61.5%, and their newborn was 99.5% (mean 25(OH)D levels: 46.3 [11.3] and 24.9 [5.4] nmol L−1, respectively). Maternal sociodemographic characteristics were similar between 25(OH)D deficient and sufficient mothers, whereas newborn 25(OH)D levels were significantly lower in the former (22.60 [4.53] vs. 27.67 [3.82] nmol L−1, respectively, P < 0.001). There was a strong positive association between maternal and newborn 25(OH)D levels (r, 0.66; r2, 43%, B [SE], 0.3 [0.02]; P < 0.001). Association of maternal 25(OH)D levels with newborn weight, length and head circumference was not significant (all P > 0.05). Our study shows a high prevalence of 25(OH)D deficiency in pregnant women and their newborns and a strong positive association between maternal and newborn 25(OH)D levels. Findings of this study indicate the importance of maintaining sufficient 25(OH)D levels during pregnancy.