Objective: Neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and monocyte-lymphocyte ratio (MLR) had emerged as useful inflammatory biomarkers in multiple diseases. The study aimed to explore the possible relationships between NLR, PLR, MLR and methylamphetamine dependence, and explore their potential wider use in clin. research. Methods: 632 methylamphetamine-dependent patients and 325 controls were enrolled. The demographics, complication of dependence, and hematol. parameters were compared. The NLR, PLR, and MLR were estimated and compared between the two groups. Result: The count of white blood cell (WBC), neutrophil, monocyte, NLR, MLR, and PLR were significantly higher and the lymphocyte count was significantly lower in methylamphetamine-dependent patients than controls (p < 0.05). Multivariate anal. showed that the NLR, MLR, monocyte, and platelet were screened as useful biomarkers to evaluate the inflammatory states of methylamphetamine dependence, resp. (NLR: OR (odds ratio) = 71.72, 95% CI (confidence interval) [27.63-186.19], p < 0.001. MLR: OR = 6.34, 95% CI [3.27-12.27], p < 0.001. Monocyte: OR = 26.34, 95% CI [3.44-206.11], p = 0.002. Platelets: OR = 3.71, 95% CI [1.97-7.02], p < 0.001). However, there were no significant differences in WBC, neutrophil cell, lymphocyte, and PLR (p > 0.05). Similar results were obtained after adjusting for age and gender. The receiver operating characteristic curve (ROC) anal. indicated that the NLR and MLR were useful parameters to identify the inflammatory states of methylamphetamine dependence (AUC (area under the curve): NLR = 0.89, MLR = 0.82, platelet = 0.64, monocyte = 0.77, p < 0.001). Furthermore, the NLR was significantly and pos. associated with severity of dependence scale (SDS) score and hallucination in methylamphetamine-dependent patients (p < 0.05). However, the MLR was uncorrelated with those variables (p > 0.05). Conclusions: The NLR might serve as a useful clin. biomarker in inflammatory states of methylamphetamine dependence, and pos. correlated with hallucination and severity of methylamphetamine dependence.