Background: Expertise in scientific and grant writing are essential in health science research and practice. Quality scientific and grant writing are uncommon in Uganda which is partly responsible for the low quality and quantity of research outputs. To address this, the Makerere University Walter Reed Project (MUWRP)implemented Strengthening Institutional Capacity for Research Administration in Uganda (SICRA). Methods: SICRA conducted 3-day face-to-face and virtual training workshops in scientific and grant writing targeting early-career scientists (ECS) at institutions involved in health research and graduate training in Uganda. Mentorship and follow-up were by phone call, email and face-to-face meetings as required. To determine the effect of SICRA interventions, we conducted a quasi-experimental impact assessment among trainees using a semi-structured questionnaire. Results: 245 ECS attended SICRA workshops on grant writing (37.2%), scientific writing (33.3%), or both(28.2%). Seventy-eight trainees (32%) participated in the impact assessment. A majority of respondents (60.3%) had a master's degree; 83% were full-time employees at a research or academic institution and 97.4% were involved in health research. Before SICRA, only 34.6%of respondents had written a manuscript, 19.2% had submitted at least one manuscript for institutional internal review and 25.6% had been published. After SICRA, 66.7% had written a manuscript (p<0.001), 51.3% had submitted a manuscript for internal review (p<0.001) and 38.5% were published (p=0.064). Before SICRA, only 37.2% had submitted a grant proposal, 24.4% had won a grant and 43.6% had participated in grant writing teams. After SICRA, 64.1% had submitted a grant proposal (p<0.001), 42.3% had received funding (p=0.011), and 62.8% were participating in grant writing teams (p=0.02). Conclusions: SICRA improved ECS scientific and grant writing which led to increased research output. The 3-day training approach is appropriate for Uganda and similar LMICs.