This paper reports the results of an analysis to determine whether derivational complexity is a determinant of item difficulty in a sentence repetition task. Fifty ESL subjects took a 26 item sentence repetition test. It was possible to estimate Rasch item difficulty indices for 18 items. The high‐difficulty items were derivationally more complex than the low‐difficulty items; however, predictions made in the early derivational complexity research about passive, negative, and interrogative sentences were not confirmed in this research. A linguistic analysis of the most difficult items suggests that this sample of ESL subjects experienced difficulties in processing adverbials, compounding and reduction of clauses, and the non‐finite verbals.