There is an increased awareness on mental health and psychiatric disorders, yet there are still unacknowledged, unmet mental health needs among patients that require admission for various medical and surgical illnesses. Consultation Liaison Psychiatry (CLP) is a specialty of psychiatry that is a multidisciplinary, collaborative delivery of service offered to patients hospitalized in general facilities. The purpose of this review is to discuss the impact and outcomes of CLP referrals on in-patients in general hospitals. An extensive research was conducted from online databases such as Google Scholar and PubMed. All studies conducted on in-patients including adults, pediatric and geriatric populations from the last ten years were included in our review. Patients undergoing CLP referrals have a reduced length of stay at the hospital in both adults and children and elderly patients 75 years and older, a significant decrease in the number of unplanned readmissions, reduced healthcare expenses and an overall improved quality of life with high social functioning when returning home.