Occupational heat exposure is an escalating concern in today's warming climate, particularly in tropical countries where temperatures routinely exceed 30 ℃. For hot and humid tropical climates such as Malaysia, the association between indoor occupational heat stress levels and renal changes remains under studied, thus necessitating in-depth investigation. A study was carried out involving several study instruments, i.e., a self-administrated questionnaire, heat monitoring device, Thermal Work Limit calculator, and for urinalysis, the analyzer used to determine Urine Specific Gravity (USG) and Albumin to Creatinine Ratio (ACR) of the respondents. The findings suggest that steel manufacturing operators are prone to heat stress and renal alteration, based on the significant evidence reported in this study. Although the results from renal changes in this study cannot be conclusively used to indicate renal damage, the need for further study with a larger sample size and in-depth analysis is indicated to comprehensively establish the situation and, if necessary, preventive measures to protect employees exposed to heat in the workplace.