Aim: The first cardiovascular risk prediction model in the Arab world was recently developed for Omanis with type 2 diabetes mellitus. This study aims to validate the newly developed model. Materials and methods: A retrospective cohort study design was applied in this study. The model was validated in two samples; the model derivation sample and a separate validation sample, consisting of 1314 and 405 diabetics respectively. All patients were free of cardiovascular disease at the baseline (2009–2010) and were followed up until: the first cardiovascular event occurred; the patient died; or up to December 2015. All data were retrieved from the patients’ medical records in a primary care setting. Results: In both the derivation and validation samples, the model showed good discrimination, with an area under the receiver operating curve of 0.73 (95% CI; 0.69–0.77) and 0.70 (95% CI: 0.59–0.75) respectively. Calibration of the model was satisfactory and the actual difference between the mean predicted and observed risk in different risk groups ranged from 0.7%–3.1% and 0.1%–4.2% in the derivation and validation samples respectively. Conclusion: The recently developed cardiovascular disease risk assessment model for Omanis with type 2 diabetes achieved adequate overall validity. The model showed good discrimination and acceptable calibration; it therefore has the potential to be used in local clinical settings. However, further validation and comparison studies are needed to judge the generalizability and superiority of the model over other tools currently used in Oman.