Nonalcoholic fatty liver disease (NAFLD) emerges as an important global burden and infection (-I) has been suggested as a risk NAFLD, although controversy exists. This retrospective study aimed to investigate a potential impact of active -I on NAFLD severity in morbidly obese patients, subjected to bariatric surgery and gastric biopsy for documentation of -I. Of 64 eligible participants, 15 (23.4%) were diagnosed with active -I, showing higher rates of nonalcoholic steatohepatitis (NASH) than those without -I (86.7% vs. 26.5%, respectively; < 0.001). Concerning histological lesions, steatosis grade ( = 0.027), ballooning ( < 0.001), lobular inflammation ( = 0.003), and fibrosis stage ( < 0.001) were also more severe in -I positive patients. Likewise, liver function tests, insulin resistance, dyslipidemia, and arterial hypertension were significantly higher in -I positive patients. -I was independently positively associated with NASH (beta = 3.27; = 0.002), severe NASH (beta = 2.37; = 0.018), and the presence of fibrosis (beta = 3.86; = 0.001) in a binary regression model, after adjustment for potential confounders. In conclusion, active -Ι was independently associated with NASH and fibrosis, findings offering potential clinical implication.