This study determined the concentrations of some heavy metals (Cd, Pb, Mn, Cu and Zn) in urine samples of patients with kidney, liver and lung related diseases (age 15-70 years); and tissue samples (kidney, liver and lung) that were pathologically abnormal from corpses (age 21-50 years) during autopsies at the Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria. It also determined the effects of age distribution, gender and life styles on the urine samples of patients with the aforementioned diseases. A total of 35 urine samples of the patients were analyzed out of which 15 had kidney related diseases, 10 had liver related diseases and 10 had lung related diseases. Four urine samples were used as controls. The urine samples were collected before meal and the age, sex, occupation and personal habit of patients were considered when taking samples. The samples were digested using microwave assisted digestion method and analyzed with Atomic Absorption Spectrophotometer. The results showed that the concentrations of Cd (0.052-0.093 µg mL −1), Pb (0.150-0.376 µg mL −1), Mn (0.014-0.278 µg mL −1), Cu (0.738-2.475 µg mL −1) and Zn (0.476-0.975 µg mL −1) in urine samples (male and female) were higher than those of the control samples (Cd: 0.035 µg mL −1 , Pb: 0.253 µg mL −1 , Mn: 0.045 µg mL −1 , Cu: 0.040 µg mL −1 and Zn: 0.716 µg mL −1) and also higher than the standard human urine levels of metals recommended by World Health Organisation. Also, Mn had the highest concentrations of all the metals determined in kidney, liver and lung tissues analysed. The study concluded that the high concentrations of heavy metals obtained confirmed the associated health complications noticed in the patients.