Background: Obesity is an undesirable outcome of changing of lifestyle and behaviours. The rapid growth in obesity represents a major public concern. It is a reversible predisposing factors for the development of several debilitating diseases, but the evolution of obesity over the lifecycle is not well understood. Broad objective The aim of this study was to determine prevalence of obesity among adults aged 18 years and above was conducted in Moshi municipality, Kilimanjaro, between December 2009 and March 2010. Design: A cross-sectional community based analytical study, conducted in Moshi Municipality, where by 252 respondents 133 females and 119 males were interviewed. Material and methods: A multistage sampling technique was used to obtain the study participants. Data collection was done through interview including demographic and socioeconomic factors, anthropometric measurements and medical examination by taking BP, RBG, and joint assessment. Results: The overall prevalence rates of obesity and abdominal obesity were 30.6% and 50.4% respectively. The prevalence of obesity in women was higher than men (p<0.001), high level of education, high economic class, place of residence, physical inactivity were associated with higher level of obesity (p<0.05) and uses of contraceptive (p<0.001), while abdominal obesity was associated with sex, i.e. female had higher waist circumference than male (p<0.001), older age, physical inactivity and use of contraceptive (p<0.05). All selected co-morbidities (Hypertension, diabetes mellitus, osteoarthritis, obstructive sleep apnea and snoring) were associated with obesity at a significantly level (p<0.05). Conclusion and Recommendation: Results of the current study indicate that obesity is increasingly and becoming a public health problem in Moshi Municipality and probably in many parts in Tanzania. Early appropriate intervention programs and management regimens are highly recommended. Further studies on large scale representative of the whole Tanzanian population are necessary to determine the extent of the problem.