Although clinical trials on intermittent-preventive-treatment (IPT) for malaria in infants (IPTi) are underway in Africa following the notable benefit of IPT during pregnancy (IPTp) using sulfadoxine-pyrimethamine (SP), evidence on the socio-economic determinants of the acceptability and viability of IPTi within infant clinic settings is inadequate. This paper reports a study on the acceptability of IPTi in two Tanzanian districts implementing IPTp using SP. Data were collected from 24 focus-groupdiscussions (FGDs) with pregnant-women and infants' mothers; interviews with 823 antenatal clients, 78 antenatal workers and 14 district health-managers among whom some also participated in FGDs. Qualitative findings indicated IPTi being appreciated among all the study population groups, considering the malaria situation. However, reservations were expressed about IPTi if SP is officially recommended. Skeptics pinpointed the sideeffects, lack of antipyretic-effect and the general treatment failures of the SP drug. Another concern was that IPTi may face operational challenges such as those currently facing IPTp implementation, including the shortage of essential supplies, poor health facility infrastructural conditions, and low numbers, skills and motivation of humanresources. Based on a hypothetical question eliciting the pregnant women's willingness to allow (WTA) their babies to receive SP for IPTi if officially SP was the drug of choice, logistic regression analysis of the data obtained indicated variations among the respondents within and between the districts about in the WTA their babies to receive IPTi-SP. In conclusion, IPTi has limited potential acceptability in the healthcare system if SP is recommended, and despite some of the respondents having expressed speculative concerns, there is need for strong public sensitization before and during IPTi implementation towards enhancement of community and frontline health-workers' compliance.