In 1963, The M. S. Hershey Foundation offered $50 million to The Pennsylvania State University to establish a medical school and teaching hospital in Hershey.  With this grant and $21.3 million from the U.S. Public Health Service, the University built a medical school, teaching hospital, and research center.  Ground was broken in 1966, and Penn State's College of Medicine opened its doors to the first class of students in 1967.   Penn State Milton S. Hershey Medical Center accepted its first patients in 1970.

Penn State College of Medicine students have gone on to become productive physicians and scientists.  The College of Medicine has granted 3,907 medical degrees and 1,300 graduate degrees.  The College of Medicine offers degree programs in anatomy, biochemistry and molecular biology, bioengineering, cell and molecular biology, genetics, integrative biosciences, microbiology and immunology, neuroscience, pharmacology, and physiology, and two postdoctoral programs leading to an MS degree in Laboratory Animal Medicine, and an MS in Public Health Sciences.  Each year, about 550 resident physicians are trained in medical specialties at the Medical Center.

Nursing students from Penn State College of Health and Human Development BS degree program rotate through the Medical Center for clinical courses each term, and students from other Penn State health-related programs and other institutions come to the campus for clinical experience.  The extended BS degree program for nurses is offered in conjunction with the College of Health and Human Development.

Continuing education programs serve Penn State Hershey Medical Center and health-care professionals throughout Pennsylvania, with enrollments exceeding 51,000 each year.

Basic and clinical research is conducted at Penn State Hershey Medical Center and is supported by more than $100 million in awards from federal, state, and private agencies, businesses, and individuals.

At the end of June 2012, Penn State Hershey Medical Center admitted nearly 27,000 patients and provided care through over 893,000 outpatient and over 64,000 emergency-service visits. Penn State Hershey Medical Center has over 9,000 employees and 400 volunteers, and the College of Medicine enrolls 800 students annually.

Sleep Research and Treatment Center

The Sleep Research & Treatment Center (SRTC) of the Department of Psychiatry at Penn State University, College of Medicine was established at UCLA by Dr. Anthony Kales in 1963 and moved to Hershey in 1971. This sleep center is one of the few that has both a sleep disorders clinic where patients are treated as well as an active research program. Because of this dual function the SRTC is well known for defining sleep/wake characteristics of various sleep disorders.

The SRTC has also played an important role in the standardization of the currently accepted adult human sleep stage criteria. Sleep stages are divided in Rapid Eye Movement (REM) Sleep and nonREM (NREM) sleep.  Sleep stage patterns are defined based upon brain wave activity (electoencephalogram [EEG], eye movements (electrooculogram [EOG]). and muscle activity (electromyogram [EMG]).  The NREM sleep stages were first described in terms of EEG by Loomis, Harvey, and Hobart in 1937. REM sleep based on eye movements and brain activity was subsequently identified by Aserinsky and Kleitman in 1954. Dement and Kleitman revised the NREM sleep stages into four and associated dreaming with REM.  Finally, loss of muscle activity during REM sleep was identified by Kales in 1964.  The need for a unified set of criteria for staging sleep was subsequently identified by Kales and in 1968 the sleep-stage scoring manual was published by Rectschaffen and Kales.  This manual brought together these three variables (EEG, EOG & EMG) in a systematic standardized manner which are the criteria used today by every sleep laboratory reporting human sleep stage data.