Objective: This study aimed to determine the predictive power of patient-related factors, socio-economic factors, condition-related factors, treatment-related factors, and health care system-related factors for nonadherence to planned coronary angiography (CAG). Material and Methods: A retrospective analysis was conducted on electronic medical records (EMR) of 665 patients appointed for elective CAG at Naradhiwas Rajanagarindra Heart Center from January 2018 to December 2019. One hundred and thirty-three patients with nonadherence to planned CAG were assigned to the study group; the control group consisted of 532 patients with adherence to planned CAG. Results: The retrospective data analysis revealed that divorced or widowed status (OR=3.07; 95% CI 1.54, 6.12), cerebrovascular disease comorbidity (OR=4.37; 95% CI 1.74, 10.96), prescribed diuretics (OR=2.24; 95% CI 1.26, 3.97), CAG wait time three months or longer (OR=3.34; 95% CI 1.46, 7.64) and history of parental cardiovascular disease or death from heart disease (OR=0.12; 95% CI 0.01, 0.95) were co-predictors of nonadherence to planned CAG. Socioeconomic- related factors had no predictive power for planned CAG nonadherence. Conclusion: The findings of this study may contribute to the improvement of nursing service by screening groups at high risk of nonadherence and developing appropriate interventions aimed at increasing adherence to planned CAG as well the rate of positive health outcomes.