People are considered mentally incapacitated if, at the time they committed an unlawful act, they were unable to understand the meaning of their actions or control their will due to mental illness, temporary mental disorder, mental disability, or some other severe mental disorder. Societal reactions to mentally incapacitated offenders are complex and include both compassion and fear. This leads to two opposing demands that the legal system must meet: helping individuals with mental disorders and protecting society from the potential danger they pose. In this paper, the author explores the complex issue of mentally incapacitated offenders and defines the key components of mental incapacity, including the biopsychological basis of mental incapacity and methods for determining mental incapacity. The paper explains in detail the specifics of criminal proceedings against a mentally incapacitated person, as well as the procedure for issuing, implementing, duration, extension, replacement, and termination of protective measures (placement in a psychiatric institution or outpatient psychiatric treatment). In addition, the paper analyzes five valid judgments of the County Court in Zadar in which the accused was mentally incapacitated tempore criminis.