Ankylosing spondylitis (AS) is associated with an increased risk of cardiovascular morbidity and mortality. Parameters, such as non-dipper, average real variability (ARV), pulse pressure index (PPI), and ambulatory arterial stiffness index (AASI) obtained from ambulatory blood pressure monitoring (ABPM), provide information about adverse cardiovascular outcomes. In this study, these indexes were evaluated in patients with AS. Sixty-five patients with AS and 65 control subjects were included in this study. Non-dipper pattern, ARV, PPI, and AASI parameters were assessed using 24-h ABPM recordings. Twenty-four-hour systolic, diastolic, mean standard deviation, PPI, ARV, and AASI were higher in patients with AS (p < 0.05 all parameters). Non-dipper (43.1% vs. 21.5%, p = 0.007) and reverse dipper (10.8% vs. 0%, p = 0.013) patterns were more common in patients with AS. In addition, disease duration was moderately correlated with AASI and ARV (r = 0.36, p = 0.003; r = 0.31, p = 0.012, respectively). This study showed that PPI, AASI, ARV, and dipper pattern were impaired in patients with AS evaluated with ABPM.