The purpose of this study was to determine whether the use of pictorial anchors improved a visual analog scale (VAS) designed to assess asthma episodes. The sample consisted of 77 children with moderate to severe asthma attending a summer camp. They rated one of two VASs, either nonpictorial (39 subjects in year 1) or pictorial (38 subjects in year 2), three times a day for 2 weeks to report the severity of their asthma symptoms. Immediately after the subjects rated the VAS, pulmonary function testing was obtained. The mean VAS scores increased 64% using the pictorial VAS while the mean PEFRs in the 2 years were almost identical, suggesting that changes on the VAS were not due to differences in pulmonary functioning. For boys, the increase in individual mean VAS score in year 2 using the pictorial VAS was 44%; for girls, the increase in individual mean VAS scores was 112%. Use of a pictorial VAS increases the range of severity of symptoms reported by children with asthma. The instrument may be a useful tool in the systematic quantifiable assessment of subjective symptomatology in pediatric asthma.