To compare mid-upper arm circumference (MUAC) with body mass index (BMI) and propose MUAC cut-off points corresponding to BMIs of <18.5 kg/m2(underweight) and ≥30.0 kg/m2(obesity) for pregnant Sudanese women, a cross-sectional community-based study was conducted in the city of New Halfa, Sudan. Healthy pregnant women were recruited. Body parameters such as height, weight, and MUAC were measured. The MUAC (cm) cut-off values for underweight and obesity were determined using receiver operating characteristic (ROC) curve analysis. Of 688 pregnant women, 437 were in early pregnancy (<20 weeks of gestation) and 251 were in late pregnancy (≥20 weeks of gestation). There was a significant positive correlation between BMI and MUAC among women in both early pregnancy (r= 0.734) and late pregnancy (r= 0.703). The cut-off points of MUAC for detecting underweight and obesity were found to be 24.0 cm and 29.0 cm, respectively, for women in early pregnancy, with good predictive values. For women in late pregnancy, the cut-off points for detecting underweight and obesity were 23.0 cm and 28.0 cm, respectively. We concluded that for Sudanese pregnant women, the MUAC cut-off points identified in the study for diagnosing underweight and obesity are both sensitive and specific.