In Indonesia, 12% or 3 million married couples suffer from infertility, with 36% of cases caused by male factors. Heat exposure, obesity, and lack of physical activity can decrease sperm quality by inducing oxidative stress and inflammation and altering the hypothalamic-pituitary-gonadal axis mechanisms. This study investigated the impact of heat exposure, obesity, and physical activity on sperm quality. This study employed an analytical observational design with a cross-sectional approach, conducted at the Sekar Fertility Clinic, Dr. Moewardi General Hospital. Sixty samples were analyzed using bivariate, multivariate, and chi 2 tests or Fisher exact test with a 95% confidence interval and p<0.05. Exposure to heat was found to increase the risk of low-sperm concentration by 74.09 times (p=0.001), obesity increased the risk of low-sperm concentration by 16.74 times (p=0.013), and low-sperm motility by 6.12 times (p=0.014), and lack of physical activity increased the risk of low-sperm concentration by 27.23 times (p=0.033). Heat exposure, obesity, and physical inactivity are associated with low-sperm concentration, and obesity is also associated with low-sperm motility.