Introduction:
Early and accurate identification of diseases and disorders is critical for patients and medical staff. Magnetic resonance imaging (MRI) offers a wide range of diagnostic applications to fulfill these expectations.

Aim:
This study aimed to determine the incidence of selected diagnoses and evaluate the population of patients examined with an MRI during the years 2011–2015 at the University Clinical Hospital in Olsztyn (UCH).

Material and methods:
The retrospective analysis of 5587 MRI scans and 5454 patients diagnosed in the MRI Laboratory at UCH was performed. Disease categories were assigned according to the International Statistical Classification of Diseases and Related Health Problems (ICD-10). SPSS software was used to determine the incidence of specific diagnoses and descriptive variables of the studied population.

Results and discussion:
More women (61%) than men (39%) were enrolled, and the diseases of the nervous system (G-letter-coded category) were predominant with one-third of patients presenting with nerve root and plexus disorders. Benign neoplasms of the nervous system were also diagnosed, but those results are beyond the scope of this article. Among symptoms, signs and abnormal clinical and laboratory findings not elsewhere classified mostly dizziness and giddiness were found, and injuries and consequences of external causes included mostly dislocations, sprain and strain of joints and ligaments of knee.

Conclusions:
The total number of MRI-diagnosed females was higher in all disease categories and age-groups, with the exception of young- and middle-aged adults 31–60 years of age in the category of injuries and consequence of external causes.