This study investigates the Critical Success Factors (CSFs) in the implementation of Project Management Information Systems (PMIS) in a small-sized nonprofit organization, European Medicines Verification Organization (EMVO), a Belgian nonprofit operating at the intersection of pharmaceutical regulation and digital infrastructure, where the Atlassian suite (Jira and Confluence) and Smartsheet were implemented during the author's internship. Drawing on direct observation, internal documentation, and stakeholder interviews, the study identifies three primary CSFs: top management support, deliberate change management centered on user adoption, and regulatory and cybersecurity readiness as a sector-specific factor. The analysis is grounded in established theoretical frameworks including Rockart's CSF model, Lewin's and Kotter's change management models, the ADKAR framework, and Greiner's and Adizes's organizational lifecycle theories.