We tested the effects of an intensive tact instruction procedure on the emission of verbal operants in non-instructional settings by three preschool students with developmental delays. The participants were selected because they emitted low numbers pure verbal operants in non-instructional settings throughout the school day. Specifically, we measured the number of pure mands and tacts emitted during probes in the non-instructional settings. During the intensive tact procedure, the participants received an additional 100 tacts above their average number of daily learn units. In a delayed multiple probe design, we found that the intensive tact instruction was effective in increasing the number of pure mands and tacts emitted in the non-instructional settings by all three of the participants in the study. (Contains 7 tables and 4 figures.)