The aim of present study is to estimate the effect of an experimental treatment on visual working memory in a child with a nonverbal learning disability (NLD). Recent researches revealed that visuospatial abilities and visuospatial working memory (VSWM) are impaired in children with NLD. The case of A.G., an 9-year-old child with a NLD is reported. Detailed psychometric and neuropsychological assessment on VSWM revealed deficits in visual and spatial-sequential working memory. A treatment targeting visual working memory was given to A.G. for eight sessions. Results showed a specific improvement of visual tasks, with the benefit of the training maintained after forty days. We also observed a generalization on geometrical tasks which seems to be related with the improvements in visual working memory.