Background: Vaccines are biological products which are used to produce or enhance immunity against vaccine preventable diseases (VPDs). Public confidence in vaccines is critical to the success of any immunization programme. For a National Immunization Programme (NIP) to achieve high and sustained population coverage, the vaccines have to be perceived as being very safe by a majority of the population. The main aim of having a functional system for pharmacovigilance of vaccines is to facilitate early detection and analysis of adverse events following immunization (AEFI) and quick and appropriate response in order to minimize negative impact to the NIP and to the health of individuals. Study objectives: The main objective of the study was to assess the Kenyan vaccine pharmacovigilance system. The specific objectives of the study were to analyse policy, law and regulations governing vaccine pharmacovigilance in Kenya; to assess the systems, structures and stakeholder coordination for vaccine pharmacovigilance; to determine signal generation and data management in vaccine pharmacovigilance; to assess risk assessment and evaluation in pharmacovigilance of vaccines; and to analyse risk management and communication in pharmacovigilance of vaccines. Study design: A descriptive cross-sectional study was conducted. Ten key informants from the Pharmacy and Poisons Board (PPB) and the Unit of Vaccines and Immunization Services (UVIS) were selected based on purposive sampling. Data were collected using the Indicatorbased Pharmacovigilance Assessment Tool (IPAT), a metric instrument designed and validated by Management Sciences for Health (MSH). The evaluation also involved review of relevant vaccine pharmacovigilance documents in the institutions assessed. A scoring system was used to quantify assessment results.