Since inflammatory diseases may also cause fibrosis, we hypothesized that patients with ankylosing spondylitis (AS) may have frequent fragmented QRS complexes (fQRS) when compared to a control group. In this prospective study, 71 patients with AS (group 1) were compared with 42 age- and gender-matched individuals without rheumatic disease (group 2, control). fQRS was described as the presence of an additional R wave (R') or R or S wave bridging, or the presence of fragmentation on two consecutive derivations that correspond to the major coronary artery regions. The mean ages of groups 1 and 2 were 37.67 ± 9.17 and 40.43 ± 11.09 years, respectively (p = 0.270). fQRS was detected in 23 AS patients (32.4%), whereas 3patients in the control group had fQRS (7.14%). Age, gender, medication, and echocardiography results were comparable. The disease duration score was 101.37 ± 59.96months in fQRS(+) patients; in contrast, it was 57.93 ± 30.95months in fQRS(-) patients. This difference was of statistical significance (p = 0.046). A statistically significant difference was not determined between the fQRS(+) and fQRS(-) groups when evaluated in terms of HLAB27 (p = 0.739). In the fQRS(+) group, the mean lumbar Schober score was 2.91 ± 1.52; in patients without fQRS, it was 4.10 ± 1.40. The mean thoracic expansion test scores in the fQRS(+) and fQRS(-) groups were 1.44 ± 0.66 and 2.69 ± 1.22, respectively. Given the higher frequency of fQRS detected in electrocardiography studies in AS patients than in the control group, cardiac fibrosis is thought to be more likely to occur in AS patients without cardiovascular disease. The presence of fQRS may be a simple and cost-effective method for predicting cardiac fibrosis in AS patients. fQRS can be a predictive marker for fibrosis in patients with AS.