Acute kidney injury (AKI) is a medical complication that can arise from various causes. This study aimed to determine the incidence of AKI and the predictors for the development of AKI in the medical wards of a tertiary hospital. A prospective cohort study was conducted on patients admitted to the medical wards from November 1 to December 31, 2017. Relevant data were obtained from the electronic hospital information system and medication charts. AKI was defined as an increase in serum creatinine (SCr) by ≥0.3 mg/dL (≥26.5 μmol/L) within 48 h, or increase in SCr to ≥1.5 times baseline, within the last seven days. Fisher's exact test or Pearson's Chi-square test was used to determine the association between characteristics of the patients and AKI. Logistic regression was used to determine possible predictors of AKI. A total of 260 patients [mean age 54.7 (19.0) years, 50.8% male] were included. Of these, 23% (n = 60) developed AKI. About 81% (n = 210) of the patients were exposed to nephrotoxic medications. Predictors of AKI were number of comorbidities [adjusted odds ratio (aOR): 4.3; 95% confidence interval (CI): 1.8-10.3; P = 0.001], diuretics (aOR: 2.8; 95% CI: 1.2-6.3; P = 0.015), proton pump inhibitors (aOR: 2.9; 95% CI: 1.4-5.8; P = 0.004), and cephalosporin (aOR: 4.5; 95% CI: 2.2-9.1; P <0.001). Mortality rate during hospitalization was similar between AKI and non-AKI patients (12% vs. 3.5%; aOR: 1.9; 95% CI: 0.5-6.7; P = 0.324). The risk of AKI is high in patients with multiple comorbidities and exposure to nephrotoxic medications. Further studies are needed to establish the role of nephrotoxic medications in causing AKI and its clinical implications.