Schizophrenia is a complex chronic neuropsychiatric disorder of the central nervous system with worldwide prevalence. The disease is thought to have multiple etiologies, including infections, genetic predisposition, and other environmental factors. There is increasing evidence pointing to a close association between chlamydial infections and schizophrenia. Here, we review the data available in the literature on the detection of bacterial species in the family Chlamydiaceae in schizophrenia and critically analyze the association and causal relationship between Chlamydiaceae and schizophrenia following the established criteria of Hill. This analysis demonstrates a probable causal relationship between Chlamydiaceae and schizophrenia. The identification of microbial agents associated with the etiopathogenesis of schizophrenia may provide new insight into the diagnosis, treatment and prevention of the disorder.