Masters ThesisChickens contribute significantly to the socio-economic development and nutritional requirements of people in Tanzania. The overall objective of this study was to investigate smallholder farmers (SHFs) preference for the tropically adapted improved chicken breeds distributed by African Chicken Genetic Gain (ACGG) project in selected Agro- Ecological Zones (AEZs) in Tanzania. This study was carried out in twelve villages which were implementing ACGG project in both Mwanza and Mbeya regions. The multi-stage random sampling was employed from AEZs level to a village level in which respondents were systematically selected from chick distribution list. The data were collected using questionnaires in which 132 SHFs were interviewed. The results show that, majority of SHFs preferred improved chicken breeds due to fast growth, disease resistance, good body shape, escape from predators, good meat taste, good egg taste and higher egg production just to mention a few. The Logistic Regression (LR) results showed that, SHFs in Mwanza region had greater improved chicken preference compared to those in Mbeya region. The profitability results show that, with the average flock size of about nine mature chickens, SHF can generate TZS 13 685 per improved chickens and TZS 6 427 per local chicken in the study areas. It is concluded that, majority of SHFs preferred improved chicken breeds which have high potential for income generation compared to local ones. It is recommended that, an economically sustainable distribution program of improved chicks to rural societies of Tanzania should be encouraged and supportedAfrican Chicken Genetic Gain (ACGG)