Background The 22q11.2 deletion syndrome (22q11DS) is one of the highest known risk factors for schizophrenia and recent findings have highlighted the clinical relevance of ultra-high risk (UHR) criteria in this population. However, studies in other at-risk populations have shown that the presence of negative symptoms (NS) is also of clinical relevance in predicting transition to psychosis. The present study examined in detail the presence and course of NS in 22q11DS, as well as their value in predicting transition to psychosis. Methods A total of 111 participants aged between 8 and 33 years were assessed with the Structured Interview for Psychosis-Risk Syndromes (SIPS). A follow-up assessment was available for 89 individuals. Results Core NS of at least moderate severity were present in 50.5% of the sample and were more severe in individuals meeting UHR criteria. They predominantly remained stable over time and their emergence between baseline and follow-up assessment was associated with significant functional decline. Some NS were significant predictors of conversion to psychosis and the emergence/persistence of psychosis risk. Conclusions Altogether, these findings highlight that NS are core manifestations of psychosis in individuals with 22q11DS that strongly impact global functioning. The presence of NS should be a primary target of early therapeutic intervention in this population.