Purpose: The aim of this study is to measure the level of knowledge among cardiac nurses about sexual counseling of post-myocardial infarction (MI) patients. Method: This descriptive cross-sectional study was conducted among 153 nurses at three tertiary care hospitals of a large metropolitan city of Pakistan. Results: The findings revealed that the majority nurses have moderate knowledge regarding post-MI sexual counseling. Additionally, nurses have lack of knowledge regarding effects of cardiac drugs on sexual life of post-MI patients. Conclusion: There is a need to improve nurses' knowledge in regard to sexual counseling among post-MI patients. Nurses should have knowledge to deal with such a sensitive issue as sexuality, in order to improve patients' quality of life. With respect to Pakistan, this was a baseline study and may provide insights for designing interventional or qualitative studies in the future.