Community health centre systems in Tanzania have been established to improve access to healthcare services for underserved populations. However, their operational efficiency and effectiveness remain under scrutiny. The study employed a Difference-in-Differences regression analysis to compare pre- and post-intervention outcomes across a subset of health centres. The DiD model accounts for temporal trends and unobserved heterogeneity through the inclusion of fixed effects for each centre and year, with robust standard errors accounting for potential confounders. The difference-in-differences analysis revealed significant efficiency gains in service delivery post-intervention, particularly in diagnostic services (25% improvement) and patient follow-up rates (18%). This study provides empirical evidence on the effectiveness of community health centre systems in Tanzania, highlighting areas for further operational improvements. Further research should focus on implementing strategies to sustain these efficiency gains and expanding coverage to ensure equitable healthcare access across all districts. Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.