This study investigated the causes of infant mortality in Akoko South West Local Government Area of Ondo State. Descriptive survey research design was used for the study while the population comprised all nursing mothers in the local government area from which 210 respondents were randomly selected as sample. Self constructed and validated questionnaire, with reliability index of 0.74 was used for data collection. With the help of two trained research assistants, the researchers administered the instrument and collected them back on the spot. The collected questionnaire forms were screened, coded into frequency tables and analysed with simple percentage and chi-square statistics. The finding showed that too frequent pregnancies, age of expectant mother, poor nutrition, poverty and lack of adequate medical care caused infant mortality in Akoko South West Local Government Area of Ondo State. Consequent upon these findings, it was recommended, among others, that free and compulsory education be provided for females up to the University level, and that teenage marriage be abrogated in the country.