In recent years, pharmacogenetics has become a powerful technique for selecting the appropriate immunosuppressant medicine and dose. Pharmacogenetics can have three different effects on immunosuppressive medication. The study of the genes that code for the drug pharmacokinetic proteins and drug breakdown enzymes is known as pharmacogenetics. The study of genetic variants that code for proteins that act as pharmacodynamic immunosuppressant trigger pathways is known as pharmacogenetics. Immunosuppressants, such as calcineurin inhibitors (e.g., cyclosporine A and tacrolimus) and antimetabolic medicines, must be used wisely for patients to survive long-term after solid organ transplantation (e.g., mycophenolic acid). Therapeutic drug monitoring and personalized therapy require the limited therapeutic index of many drugs and vital interindividual and individual variability in pharmacokinetics (PK) and pharmacodynamics (PD). Genetic polymorphisms along with immunosuppressant PD have received more attention in recent years. Monitoring these pharmacogenetic indicators gives us an excellent tool for developing personalized immunosuppressant dose regimens. The findings of the studies on the prospective genes mentioned above and the improvement of omics methodologies may one day permit us to choose the suitable immunosuppressant for the particular client at the appropriate dose.