Background Infant and childhood is the best period to assess the growth of an individual since it can have a long-term consequence during adulthood. Poor growth is associated with impaired development which is apparent in the relationship between growth status and school performance and intellectual achievement. Poor growth pattern among infants has been reported to be a major problem in many low- and mid-income countries. As part of the strategies of WHO to reduce underweight and malnutrition by 40% by 2025, it is important to understand the factors associated with underweight and overweight for under five. Objectives The objective of this study is to determine factors influencing growth pattern of infants attending antenatal care visits at Pasua primary health center. Methodology This was a hospital based cross section study, conducted from April to June 2016 among infants aged 6 months to 12 months at Pasua health Centre in Moshi district. Convenience sampling was used to get the study participants. Structured questionnaires was used to collect key information during a face to face interview. Additional information were collected from infant’s antenatal clinic card. Data was entered and analyzed by using SPSS. Results 185 mothers participated in the study. The prevalence of underweight among infants was 15.1, strong association between growth of infants and maternal socio economic was observed where by infants who their mothers were employed had increased odds of becoming underweight compared to infants whom their mother were not employed. and the main diseases encountered by infants were RTI and diarrhea. Conclusion Strong association with maternal socio economic factors was found, insufficient knowledge on the part of mothers and lack of efficient systems of informing them on breastfeeding issues were seen to be the major problems followed by recurrent respiratory tract infection and diarrhea which was due to not practicing exclusive breastfeeding