We aimed to evaluate diagnosis delay and its impact on disease in terms of activity, functional disability, and radiographic damage in Moroccan patients with ankylosing spondylitis (AS). We recruited 100 Moroccan patients who fulfilled New York Classification criteria for AS. Diagnosis delay was defined as the interval between the first symptom of AS and the moment of a correct diagnosis. Disease activity was evaluated by the bath ankylosing spondylitis disease activity index (BASDAI), functional status by the bath ankylosing spondylitis functional index (BASFI), and radiographic damage by the bath ankylosing spondylitis radiologic index (BASRI). Measurements of spinal mobility were assessed. The average age at disease onset was 28.56 ± 10.9 years. Of the patients, 16% had juvenile-onset AS. Disease duration was 9.5 ± 6.8 years, and the average of diagnosis delay was 4.12 ± 3.99 years. There were no differences in diagnosis delay according to the age at onset, educational level, or the presence of extra-articular involvement. Our patients had altered functional ability. Patients with late diagnosis (>5 years) had statistically significant higher structural damage (BASRI) and severe limited spinal mobility. There was no correlation between diagnosis delay and the activity of disease. Few studies focused on diagnostic delay and its impact in patients with AS. It is necessary in our context to establish an early diagnosis taking into account the high frequency of severe functional disability in Moroccan AS.