To determine longer-term efficacy of botulinum treatment, the author examined 85 children younger than 14 years of age who had been treated from November 1982 to February 1984, comparing shorter follow-up (range, 6-24 months) with longer follow-up (range, 2-5.5 years) as of last examination before March 1988. Fifty esotropes meeting the 2-year criteria for follow-up had an average of 35 prism diopters (PD) before and 5 PD after treatment. Twelve exotropes averaged 30 and 5 PD. No long-term complications were discovered. The results are similar to the shorter follow-up and suggest that botulinum is effective in creating a 2- to 5-year stable improvement for strabismic children.