Introduction: Section 5(ii) of The Hindu Marriage Act, 1955 (HMA) states that under certain circumstances, mental illness is accepted as a ground for the annulment of marriage, while Section 13(1) (iii) states that mental illness is a ground for divorce. There is little data on how this provision is used and applied in matrimonial petitions. This paper assesses judicial practices in divorce cases, exploring the extent to which gender and the diagnosis of mental illness affect the decision to grant annulment or divorce. Methods: The paper analyses judgments related to annulment and divorce at the Family Court in Pune and at the High Courts in India. Results: In the Family Court at Pune, 85% of the cases were filed by husbands, who alleged that their spouse was mentally ill. Medical evidence of mental illness was presented in only 36% of the cases and in many cases, divorce/nullity was granted even in the absence of medical evidence. In 14% of the cases, nullity/divorce was granted even when both spouses were not present. Of the Family Court cases reaching the High Court, 95% were filed by male petitioners. The High Courts reversed the lower courts' judgments in 50% of the cases. Discussion: Our analysis highlights the need for standardised guidelines for lower courts on what constitutes adequate medical proof of mental illness when hearing a petition related to nullity or divorce under HMA. It also provides a critical review of Section 5(ii) of HMA.