The thesis aims to evaluate factors pertaining to reporting Adverse Drug Reactions (ADRs) among healthcare professionals- medical doctors and pharmacists- in Nigeria by conducting a questionnaire-based survey and phone interviews for quantitative and qualitative analysis respectively. To achieve this, the knowledge, awareness and challenges faced by medical professionals in relation to ADR reporting were considered in order to determine effective recommendations to improve ADR reporting practices and pharmacovigilance in Nigeria. Both groups of healthcare professionals were compared to determine their opinions on frequency of observed and reported ADRs, reasons for high underreporting rates, awareness of ADR reporting methods, guidelines and regulations as well as the NAFDAC regulatory body responsible for handling submitted ADR reports. A total of 104 out of 140 responded to the survey, of whom 53 (75.7%) were medical doctors and 51 (72.9%) were pharmacists. Interestingly, 34.0% of medical doctors who responded did not know how to report ADRs compared to just 5.9% of pharmacists who responded. From the analysis conducted, the pharmacists had better knowledge, awareness and experience over medical doctors regarding ADR reporting in Nigeria. However, an overwhelming 90.0% of both groups of respondents opted for ADR reporting being made compulsory as a professional obligation towards pharmacovigilance. The inaccessibility of ADR report forms when needed, complex reporting procedures, busy work schedules and lack of time remained the most challenging factors to ADR reporting while fear of legal liabilities or the clinical knowledge to identify ADRs were among the least challenges reported. Organising pharmacovigilance conferences and continuous education programs to improve awareness among healthcare professionals and including ADR reporting courses during undergraduate