Background: Our aim in this study was to evaluate the effect of a combined educational intervention and year-long monthly text message reinforcements via the Short Messaging System (SMS) on the knowledge, attitude and practice (KAP) of healthcare professionals (HCPs) towards pharmacovigilance. Methods: Six randomly selected teaching hospitals in the South-South zone of Nigeria were randomized in 1:1 ratio into intervention and control groups. The educational intervention consisted of delivering a seminar followed by sending monthly texts message reinforcements via SMS over 12 months. Then a semi-structured questionnaire regarding the KAP of pharmacovigilance was completed by HCPs working in the hospitals after the intervention. Data was analysed descriptively and inferentially. Results: A total of 931 HCPs participated in the post intervention study (596 in the intervention and 335 in the control). The M:F ratio was 1:1.5. According to the KAP questionnaire, a significant difference was observed between the intervention and control groups, regarding knowledge of the types of adverse drug reactions (ADRs). ADR resulting from pharmacological action of the drug (85.6% versus 77%, p = 0.001), the fact that ADRs can persist for a long time; (60.1% versus 53.4%, p = 0.024) and a higher awareness of the ADR reporting form (48.7% versus 18.8%, p < 0.001). Most respondents in the intervention group (68.5% versus 60.6%, p = 0.001) believed they should report ADRs even if they were unsure an ADR has occurred, a greater proportion of HCPs from the intervention group had significantly observed an ADR (82% versus 73.4%, p = 0.001). Furthermore, of the 188 who had ever reported an ADR, 41% from the intervention group used the national ADR reporting form compared with 19.8% from the controls (p < 0.001). Conclusion: This educational intervention and the use of SMS as a reinforcement tool appeared to have positively impacted on the knowledge and practice of pharmacovigilance in South-South Nigeria with a less-than-impressive change in attitude. Continuous medical education may be required to effect long-lasting changes.< Réduire