Abstract: Previous research has shown that various prompting procedures are effective in teaching skills to children and adults with developmental disabilities. Simultaneous prompting includes proving a prompt immediately following an instruction; whereas constant time-delay procedures include a set time delay (i.e., 5 s or 10 s) prior to delivering a prompt following an instruction. These prompting procedures have been previously compared with mixed results. The current study used an alternating treatments design to compare simultaneous prompting to a constant time-delay procedure to evaluate efficacy and efficiency of each procedure, in addition to the number of errors which occurred under each condition. Results from the current study are discussed as well as limitations and future directions.