Language disorders are not exclusive to speech perception: SLI is also observed in deaf signers (Mason et al., 2010). The phonological deficit is a robust marker of language disorder in vocal languages and the same can be expected in signed languages (Herman et al, 2013). Given that many morphosyntactic cues are based on signed phonology, a phonological deficit may lead to a morphosyntactic deficit. To evaluate and quantify this type of language disorder or atypical development, it is necessary to test linguistic skills. To date, no specific tests allow caretakers or researchers to assess those skills. To our knowledge, no assessment tool for LSF exists. In the wake of Courtin’s work on LSF assessment, and other sign-language assessment tools (Haug, 2008), our general goal is to develop an arsenal of tests to assess linguistic abilities in LSF. In the present study we focus on LSF phonology. We evaluate phonological ability by using a non-sign repetition task and a non-sign discrimination task in children aged from 4 to 9. Items were contrasted on each of the five parameters: handshape, orientation, placement, movement, and facial expression. Three groups were tested: Deaf signing Children of Deaf Parents (DCDP), Deaf signing Children of Hearing Parents (DCHP) and Hearing Children of Hearing Parents (HCHP). Non-sign stimuli were used in order to measure accurately their phonological ability, while avoiding participants relying on their lexical skills. As expected, DCDP were more accurate in non-sign repetition and succeeded in discriminating contrastive pairs, compared to DCHP and HCHP. These results are discussed in terms of age of LSF acquisition and its mastery, atypical development vs. specific disorder, sign language knowledge vs. coverbal gestuality, and the contrastive impact of each kind of parameter.