Data from the National Ambulatory Medical Care Survey show a steady increase in the number and rate of physician office visits for otitis media over the period from 1975 to 1990. The annual visit rate during this period more than doubled, and for children under age 15, increased 175 percent. Though the increase is greatest for males under age 2, there are substantial increases for males and females under age 15. Reasons for this dramatic increase are not readily apparent. Data from the National Health Interview Survey (NHIS), however, suggest that the increased visit rate may reflect an increase in the incidence of ear infections. According to NHIS data, the incidence of acute ear infections among the U.S. population increased by about 40 percent between 1982 and 1990, from 6.1 to 8.6 conditions per 100 persons per year. This compares with an increase of about 52 percent in the physician office visit rate for otitis media, from 1980 to 1990. (Because of gaps in data collection, it is not possible to compare precisely concurrent time periods.) The under 15 age group, which accounts for about 80 percent of otitis media physician office visits, experienced a 60 percent increase in office visit rate from 1980 to 1990. This parallels data from the NHIS that show a 60 percent increase in the incidence of acute ear infections among the under 17 age group from 1982 to 1990. The reporting of an acute ear infection in the NHIS does not necessarily equate to an incidence of otitis media, but the parallel increases in ear infection incidence and otitis media physician visits are mutually supportive and likely to be related.