In the course of normal classroom lessons, 103 students (median 11.10 years) were asked to spend 15 min writing "anything you can think of" about the number 50 on a blank page. The products were independently scored by 2 specialist art teachers and 2 specialist mathematics teachers on criteria relevant to their specialisations. Immediately before this task, however, half the students (depleted group) worked on difficult matching problems for 3 min, whereas controls worked on facile problems. Although volume of creative response appeared only marginally affected, depleted students were rated as lower on overall creativity (d?=?0.8) by the arts teachers. The mathematics teachers also rated the depleted students as showing less quality in their work (d?=?0.97). The depleted students cited fewer mathematical statements, but displayed more errors in statements they had written. The findings were interpreted in terms of ego depletion effects upon creativity.