Hospitalists are physicians who specialize in the care of patients in the hospital. The majority of hospitalists are board-certified internists and have completed the same training as other internal medicine doctors including medical school, residency and board certification examination.
Hospitalist activities include patient care, teaching, research, and leadership related to hospital care. They have more expertise in caring for complicated hospitalized patients on a daily basis since, unlike other specialists or primary care doctors, they spend most of their day in the hospital.
They often coordinate the care of their patients and act as the central point of communication among the different doctors and nurses involved in the patient's care. They are also the main physician for family members to contact for updates on a loved one.

An internist is a physician who focuses on the diagnosis and treatment of conditions that affect the adult population—both acute and chronic.
These doctors are often who adults see as their primary physicians because they treat a broad range of illnesses that do not require surgical or specialist interventions. They also work to help a patient maintain optimal health in order to prevent the onset of disease.
In addition to treating the common cold and flu, internists also treat chronic diseases like diabetes and heart disease.

A family practitioner is a doctor who specializes in caring for people of all ages, at all stages of life. Rather than focusing on the treatment of one disease or patient population, family practitioners are often the doctors that people see for their everyday ailments, like cold and flu or respiratory infections, and health screenings. When necessary, family practitioners will provide referrals for conditions that require the expertise of another specialist.
The doctors may also provide physicals, inoculations, prenatal care, treat chronic diseases, like diabetes and asthma, and provide advice on disease prevention.