Background: Anaemia is among of the major cause of mortality and morbidity among women of reproductive age worldwide. In low-income countries it accounts for 26% of all deaths in women of reproductive age. Anaemia during pregnancy is an important factor associated with increased risk for poor pregnancy outcomes such as intrauterine growth retardation, premature delivery, low birth weight and increased susceptibility to infection, resulting in an increase in perinatal mortality. To combat this, the government of Tanzania through its ministry of health and social welfare has been intervening by ensuring that pregnant women receive folate and iron supplements during their entire pregnancy period. Determining the prevalence and factors contributing to anaemia may help us to understand its burden and design strategies and interventions to supplement the current ones so to reduce the mortality and morbidity associated with anaemia. This may help to accelerate towards the achievement of SGDs. Objective: This study aims to determine the prevalence of anaemia and its associated risk factors among women of reproductive age in Northern and Southern Tanzania. Methodology: This was a cross-sectional analytical study conducted from April-June, 2016, as part of a survey done in November 2015, of the national food fortification program launched in May 2013. The purpose of the program was to be a cost effective intervention to prevent and reduce micronutrient malnutrition. A multistage simple random sampling in which 1302 women of reproductive age participated from six districts of Tanzania; Iringa rural, Kilolo, Njombe, Karatu, Arumeru and Monduli. Questionnaires were used to collect information on demographic data and information on maternal age, educational, and socioeconomic and nutritional status. Blood hemoglobin levels was measured using HemoCue and categorized according to WHO categories for anaemia. Data analysis was done using SPSS version 23 and descriptive statistics were used to summarize the categorical variables. Measures of central tendency and their respective measures of dispersion were used for continuous variables. Chi-square test was used to determine the relationship between a set of independent variables and the severity of anaemia. Odds ratio with 95% CI for factors associated with anaemia was estimated using multivariate logistic regression models. A P-value of less than 0.05 was considered statistically significant. iii Results: Our results showed that majority (86.6%) of the study participants were anaemic. Anaemia was more prevalent in the North (52.7%) than in the South (47.3%). The risk factors for anaemia that were identified were; rural residency (AOR: 3.91; 95% CI: 2.847-5.364), being underweight (AOR: 1.21; 95%CI: 0.516-0.827-) and being of the age group of 15-19years. No significant association was found with education level, weekly meat consumption, number of children, marital status, occupation or knowledge on micronutrients. Conclusion: We found the prevalence of anaemia to be 86.4% in general, Anaemia was more prevalent in the North (52.7%) than in the South (47.3%). Age, residency and BMI of study participants were significantly associated with anaemia. Strategy to promote the importance of nutrition in preventing anaemia in the study areas is warranted.