This study was aimed at studying management, productivity and socio- economic attributes of guinea pigs (GP) in Njombe district. Two separate studies were conducted. A survey was done among 72 households and results indicated that GP were owned by most of the households. The majority (93.1%) of farmers who keep GP practise intensive production system. GP were found to be a good source of meat (35.5%) manure (32.8%) and for income (17.5%) to farmers. The mean weights of sampled GP measured at the farmers’ households were 571.3 ± 8.71, 548.9 ± 8.25, 233.5 ± 2.19, 231.6 ± 2.38, 126.4 ± 3.52, 127.1 ± 3.18 g for mature males, females, growing males, females, young males and females, respectively. A planned experiment was conducted involving 60 GP aged one month and fed 5g (T1), 20g (T2) and 30g (T3) of concentrates for 4 months. Data were analysed using General Linear Models of SAS for effects of sex, origin and diets. Results showed that the effect of sex on body weights at the 2 nd , 3 rd , 4 th and 5 th month and carcass traits was not significant (P>0.05). Further, effect of origin of GP on weights and carcass traits was insignificant though GP from Ramadhani had significantly higher (335.6 ± 9.09 g) mean initial weight and final weights (551.9 ± 8.59 g) compared to those from Itulike (with respective weights of 292.6 ± 9.09 and 508.9± 8.59 g). Dietary treatment had significant (p<0.01) effect on monthly weights and carcass weight expressed as percent of slaughter weight. Weights and weight gains increased with increase in feeding level. Daily weight gains were 1.1 ±0.04, 2.1±0.04 and 2.2±0.04 for T1, T2 and T3 respectively. Their corresponding final weights were 473.6 ±10.5, 528.7±10.5 and 588.8±10.5 g. It was concluded that experimental GP were heavier in early stage of growth than those from surveyed farms indicating that native GP can do well under good management practices.