Mother-to-infant vertical transmission of HIV usually occurs during pregnancy, labor, delivery or breastfeeding. It is the third leading cause of transmission of HIV after sexual intercourse and blood transfusions. In 2008, 12 million women aged 15 years and above were anticipated to be living with HIV in countries within Sub-Saharan Africa. In this study, the association between parental HIV knowledge, attitudes and risk reduction practices, and HIV vertical transmission in Kenya were explored. The health belief model was used to help understand and interpret the findings. For this quantitative study, data were collected via surveys from 212 participants in 3 HIV clinics in Kenya. Data were analyzed using descriptive and inferential statistics. Around 45% of respondents lacked knowledge on key aspects of Prevention of Mother to Child Transmission (PMTCT) of HIV particularly on expressing and heat treating milk from HIV positive mothers to make it safe for their babies. About 65% of Participants had awareness towards Mother to Child Transmission (MTCT) of HIV. Logistic regression showed no association between socioeconomic factors and parental knowledge on MTCT of HIV. Logistic modeling found that there was association between attitude and MTCT, revealing that attitude increased the likelihood to influence MTCT. Being married was associated with reduced risk of MTCT of HIV. The overall results indicated gaps in knowledge and information packaging. The potential positive social change implication of this study is that factors related to HIV vertical transmission identified in this study might be utilized to develop and implement HIV prevention strategies to reduce HIV vertical transmission and decrease associated morbidity and mortality among this vulnerable population.