Diagnoses for which antibiotics are sometimes indicated were otitis media, sinusitis, pneumonia, and streptococcal pharyngitis. Diagnoses for which antibiotics are never indicated were acute bronchitis, nonspecific upper respiratory infection, influenza, and nonstreptococcal pharyngitis. Linear trend in session hours (combining 8 AM with 1 PM, 9 AM with 2 PM, 10 AM with 3 PM, and 11 AM with 4 PM): P < .001 for antibiotics sometimes indicated; P < .001 for all acute respiratory infection visits; and P < .002 for antibiotics never indicated. During clinic sessions, the proportion of acute respiratory infection visits for which antibiotics were sometimes indicated did not vary significantly from hour to hour (P = .64).