Background: Women in the reproductive age group are most vulnerable to malnutrition. Maternal and child undernutrition is the underlying cause of 3.5 million deaths each year and 11 % of the total global disease burden. Among women in sub-Saharan Africa, 10-20 % are classified as excessively thin. The 2011 Ethiopian Demographic and Health Survey (EDHS) has reported that 27 % of Ethiopian women and 40 % of Tigray women of reproductive age are too thin. There is no previous study done on the nutritional status and associated factors of women of reproductive age among Kunama women, the minor group. The aim of the study is to assess the magnitude of chronic energy deficiency and its associated factors among women of reproductive age in the Kunama population in Northwest Tigray, Ethiopia, in 2014. Methods: A community-based cross-sectional study was conducted in the Tahtay Adiyabo woreda, Northwest Tigray, Kunama population on 284 women of reproductive age who were selected using simple random sampling technique. Data was collected using structured face-to-face interview and anthropometric assessment from January 27 to March 7, 2014. Data were entered and analyzed using SPSS version 20. Logistic regression was done to identify factors that are associated with undernutrition. Results: The prevalence of undernutrition/chronic energy deficiency (body mass index <18.5 kg/m 2 ) was 47.9 % (95 % CI 42.11-53.7 %). Severe (BMI <16 kg/m 2 ), moderate (BMI <17 to ≥16 kg/m 2 ), and mild undernutrition (BMI <18.5 to ≥17 kg/m 2 ) was detected in 6.3, 10.6, and 31.0 % respondents, respectively. Age at first marriage (AOR = 2.76, 95 % CI 1.45, 5.25), household food insecurity (AOR = 2.15, 95 % CI 1.05, 4.41), inadequate dietary intake (AOR = 2.93, 95 % CI 1.53, 5.59), time to fetch water (AOR = 2.31, 95 % CI 1.22, 4.41), and meal frequency (AOR = 2.0, 95 % CI 1.003, 3.99) were found to be independent predictors of undernutrition. Conclusions: The prevalence of undernutrition was relatively high among women of reproductive age in the Kunama community. Providing comprehensive and routine nutritional assessment, counseling women at all levels, and increasing involvement of organizations are recommended to address and prevent malnutrition.