In this study the effect of a stimulus-stimulus pairing procedure was used as part of a clinical investigation to increase vocalizations for two young children diagnosed with autism. This procedure involved pairing a vocal sound with a preferred stimulus (e.g., toy) to condition automatic reinforcement. In addition, this study assessed the effects of a direct reinforcement procedure to bring a vocalization under echoic control following the pairing procedure for 1 of the participants. The results showed the pairing procedure was used successfully to increase a vocalization for one of the participants, and the vocalization was brought under echoic control. (Contains 4 figures.)