: In Thailand, the transition of primary care units (PCUs) to Local Administrative Organizations (LAOs) has raised concerns regarding the potential impact on healthcare service delivery. This study aimed to compare health services between PCUs that have been transferred to LAOs and those that have not. : A total of 15 transferred PCUs (T-PCUs) and 45 non-transferred PCUs (NT-PCUs), matched by population within the same provinces, were purposively sampled. The study population consisted of the cumulative number of diabetes (DM) and hypertension (HTN) screenings retrieved from the National Health Security Office (NHSO) database from 2017 to 2023. The impact of the LAO transfer policy on health service delivery was assessed using generalized estimating equation (GEE) models. All analyses were performed using Stata version 15. : The result showed no significant difference in the population and size of PCUs. DM screening was non-significantly lower by 18.9% (AdjRR: 0.811), and HTN screening was lower by 18.6% (AdjRR: 0.814), when comparing T-PCU with NT-PCU. Similarly, the DM and HTN screening in T-PCU was non-significantly lower than NT-PCU when interacting with time. Both T-PCU and NT-PCU show decreases over time; however, the decrease was not statistically significant. : Our results show a non-significant difference in DM and HTN screening between T-PCU and NT-PCU. Therefore, decentralization did not clearly demonstrate a negative impact on the delivery of these health services. Further research is needed to consider other confounding and covariate factors for DM and HTN screening.