BACKGROUND Negative symptoms are a core feature of schizophrenia. The evolution and trajectory of primary negative symptoms were under-studied. We aimed at evaluating the prevalence and stability of primary negative symptoms, and factors associated with persistent primary negative symptoms in a first-episode sample. METHODS Ninety-three Hong Kong Chinese aged 18 to 55 years presenting with first-episode schizophrenia-spectrum disorder were studied. Data on premorbid adjustment, socio-demographics, and baseline clinical and cognitive profiles were obtained. Psychopathological and vocational reassessments were conducted at 12, 24 and 36 months. Primary negative symptoms were defined as the presence of clinically significant negative symptoms excluding depression and extra-pyramidal signs. RESULTS At baseline, 25.8% of subjects exhibited primary negative symptoms. A quarter of patients had their initial primary negative symptoms status retained 12 months after treatment initiation. In both Year 2 and Year 3 of study period, around 70% of subjects had their primary negative symptoms status maintained for 12 months. At the end of three-year follow-up, 23.7% were categorized as having persistent primary negative symptoms. Male sex, unemployment at intake, prolonged duration of untreated psychosis, poorer premorbid academic and social functioning, poorer insight and worse vocational outcome were found to be associated with persistent primary negative symptoms. CONCLUSIONS Clinical status of primary negative symptoms in first-episode schizophrenia-spectrum disorder was unstable in the initial year of treatment. Baseline symptom assessment may not reliably predict development of persistent primary negative symptoms. Studying negative symptoms should take into account the longitudinal perspective, especially in the early course of psychotic disorders.