Introduction: The Democratic Republic of Congo (DRC) does not have national prevalence data for arterial hypertension (HTN) or diabetes (type I and II combined) to aid evidence-based decision-making, despite the assumption of epidemiological transition in low- and middle-income countries. The aim of this study was to estimate a proxy of prevalence for HTN and diabetes. Methodology: This study used routine monthly reported data pertaining to HTN and diabetes from the District Health Information Software 2 (DHIS2), spanning 2019–2023. Data underwent quality assessment and adjustments using standardization before analysis. Equity analyses were carried out at the national and sub-national levels. Epidemiological curves and maps were produced to analyze trends in the prevalence of HTN and diabetes among adults aged 18 and over. Permission to use the data was obtained from the regulatory authority. Results: Over five years, incidence of HTN increased from 13.23% (CI 95%: 13.22–13.24) to 15.23% (CI 95%: 15.22–15.24) (+15.1% relative increase), and diabetes rose from 2.73% (CI 95%: 2.72–2.74) to 3.345% (CI 95%: 3.34–3.35) (+16.3% relative increase), with provincial variations observed. Conclusions: In the DRC, hypertension and diabetes are advancing rapidly. Primary and preventative healthcare services and public health interventions must prioritize these diseases.