Objectives The aim of the study was to evaluate the appetite-stimulating effect of gabapentin by comparing it with mirtazapine in healthy cats in the first 8 h after ovariectomy surgery. Methods This double-masked, placebo-controlled, prospective clinical trial included 60 healthy cats presented to the hospital for ovariectomy: 20 received gabapentin, 21 received mirtazapine and 19 received a placebo immediately before and 6 h after surgery. Food was offered at 2, 4, 6 and 8 h post-ovariectomy. After each meal, food intake was measured. Data were analysed using repeated-measure ANOVA and a linear mixed-model analysis. Post-hoc Tukey's honest significant difference test was performed for multiple comparisons. Results Food intake increased in both treatment groups vs placebo. No statistically significant difference was found between cats treated with gabapentin or mirtazapine. Conclusions and relevance Cats receiving gabapentin ate more than cats in the placebo group. Thirty percent of cats in the gabapentin group covered their resting energy requirements, while none of the cats in the placebo group did. Gabapentin and mirtazapine produced similar effects on food intake.