Objective: The aim of the study is to assess the effect of tobacco smoking on the risk of nonfatal acute myocardial infarction in young adults less than years. Materials and Methods: We conducted a population-based case-control study with 164 occurrence acute myocardial infarction cases (21 women; 143 men), consecutively visited King Abdulaziz hospital, KSA, and 227 controls (81 women; 146 men), From February2016 till February2017. All women are non-Saudi women. Odds ratios (OR) and 95% confidence intervals (95%CI) were calculated using unconditional logistic regression. Results: The commonness of present smoking was 81% in male cases and 54% in male controls (OR = 3.59, 95%CI: 2.49, 5.31) and 60% of female cases were smokers compared with 36% of controls (OR = 2.65, 95%CI: 1.40, 4.98). No interaction was found between current smoking and gender on myocardial infarction risk (P = 0.399). A dose-effect response was present, the odds favoring myocardial infarction reaching an eight-fold increase for those who smoked >25 cigarettes/day compared with never smokers. The risk estimate for former smokers was similar to never smokers. Conclusions: Tobacco smoking is an important independent risk factor for acute myocardial infarction in young adults, with similar strength of association for both genders.