There are 2.6 million vulnerable children in Kenya. In the past, vulnerable children were taken care of by their kin, through informal arrangements. Today, a good number of vulnerable children are forced to find shelter in institutions such as children’s homes while others are forced to live in the streets. In 2014, the government of Kenya introduced the concept of alternative family care (AFC) with the view of replacing institutional care in addressing the problem of vulnerable children. Various AFC arrangements were introduced including adoption, foster care, guardianship, and kinship care. The purpose of the proposed study was to examine the influence of family structure on the choice of AFC arrangement offered to vulnerable children in Nakuru East Sub-County. The study was guided by Bowlby’s Attachment Theory. It utilized the descriptive survey design where data was collected through the use of questionnaires. The questionnaires contained both open-ended and close-ended questions. The target population comprised of 244 caregivers who were involved in some form of AFC in the 2016/17 financial year within the study area. The population was stratified in terms of the AFC arrangement in which the subjects were involved (adoption, foster care, guardianship, or kinship). From this population, a sample of 123 participants was selected using the proportionate stratified sampling method and 102 were able to complete the study. Data was analyzed using both quantitative and qualitative methods. Findings revealed that family structure particularly family type, family size, and family relationships have a statistically significant influence on choice of AFC. The study recommends that the government and other stakeholders should increase finance and other forms of support to caregivers in kinship care as findings show that the majority these caregivers have large family. Stakeholders should also raise awareness regarding the other form of AFC especially adoption, foster care and guardianship as there is the misconception that these AFC arrangements are for individuals who do not have biological children.