M.SC. DISSERTATION.This study aimed at undertaking a comparative analysis of farm power technologies; manual, oxen, 2WT and 4WT in Rice Production for Smallholder Farmers in Mbarali District, Tanzania. The study had three objectives namely: (i) identification of different farm operations by power sources used by smallholder farmers in paddy production, (ii) analysing costs and returns per unit area of using the mentioned sources of farm power and (iii) examining factors influencing smallholder farmers’ choice of farm power technologies for use in selected farm operation. Purposive and random sampling techniques were employed in selecting 240 smallholder rice farmers. Descriptive statistics, partial budget approach and binary logistic regression model were used in data analysis. Results show that different types of farm power were used to suit specific farm operations. In most cases operations like land clearing, transplanting, weeding, and fertilizer applications were normally done manually. On the other hand, tilling and puddling operations were done by manual, draught animal, 2WT or 4WT power with the exception of 2WT being used mostly compared to other farm power . Considering tilling and puddling using manual power or 4WT as current practices, partial budget results indicated a positive net change implying that a farmer will be better off when choosing to use 2WT technology. Considering tilling and puddling using oxen as current practices, partial budget results indicated a negative net change implying that a farmer will be better off continuing with the use of oxen than the proposed change of using 2WT. The binary logistic results to establish factors affecting choice of technologies show that, the highly statistically significant variables at 1% (P<0.01) and 5% (P<0.05) level are time, availability of technology and age of household head. These findings suggest that an adjustment in each one of the significant variables can significantly influence the probability of using the farm power technologies. Based on the findings of the study the following recommendations were made; (a) farm power technology especially machines should be made available and affordable at the proper time for use, (b) supply of quality and durable farm power with more attachments to enable carrying out multi-operations, and (c) conducting thorough research on the needs of farmers in a targeted area priori to supplying of farm machinery.