Assessment is essential for designing individualized educational plans (IEPs) for children. In order to contribute effectively to this process, assessments must be appropriate for the group, show neither floor nor ceiling effects, and help teachers formulate specific aims. Different attempts to develop such assessments for the writing of deaf primary school children have shown floor effects. This paper reports the validation of an analytic instrument aimed at assessing deaf primary school children's writing and at contributing to the design of IEPs. Participants (N = 167) were deaf children in the age range 6y6m to 13y11m, who were attending special schools or mainstream schools with units for the deaf; orally educated deaf children fully integrated in mainstream schools were not included. The writing samples were elicited by means of a story picture sequence. The dimensions of analysis included 16 items related to aspects of grammar and story development. A single and reliable scale was formed by these items, generating one score with a normal distribution. High inter-judge reliability, high test-retest correlation and a high correlation with reading comprehension were observed. We conclude that the assessment is a useful, reliable and valid instrument for analysis of deaf children's writing. (Contains 4 tables.)