Aim: We aimed to investigate whether, and to what extent, plasma glucose and lipid concentrations and body mass index (BMI) values, influence schizophrenia severity in Croatian patients, according to their smoking status. Patients and methods: Our study comprised 263 chronically ill patients (males/females: 139/124). Severity of schizophrenia was assessed via Positive and Negative Syndrome Scale (PANSS) psychopathology data during an acute illness state at the time of last hospital admission. Smokers were defined as individuals who smoked more than one cigarette each day for more than one year, and nonsmokers were defined as those who had smoked fewer than 100 cigarettes during their lifetime. Results: Plasma triglyceride and glucose levels and BMI values were not associated with PANSS psychopathology, neither among males, nor among females, according to their smoking status (all P > 0.05), whereas data of PANSS psychopathology among females were associated only with plasma cholesterol concentrations. Female smokers with higher LDL cholesterol (engl. low density lipoprotein cholesterol) concentrations had significantly lower general and total PANSS symptom values (P = 0.023 and P = 0.015), whereas among female nonsmokers with greater HDL cholesterol (engl. high density lipoprotein cholesterol) concentrations, significantly lower positive and total PANSS symptom values were observed (P = 0.041 and P = 0.002). The LDL cholesterol concentrations account for approximately 20% of the general symptom variability and 23% of the total symptom variability among female smokers; among nonsmoking females, HDL cholesterol concentrations contribute by approximately 39% to positive symptom severity and by approximately 69% to total symptom severity. Conclusion: According to our results, we can conclude that plasma cholesterol concentrations influence schizophrenia severity in female patients only. Furthermore, the contribution of cholesterol concentrations to PANSS psychopathology varies from small to moderate.