Objective: Abnormal iron handling complicates pulmonary hypertension and causes functional limitation and poor outcomes. Although preliminary results in group 1 pulmonary hypertension patients support the use of iron replacement, whether this applies to other PH subgroups is not known. Methods: A total of 58 patients with an established diagnosis of group 1 or 4 pulmonary hypertension, who had serum ferritin of <100 ng/mL or 100-300 ng/mL in combination with a transferrin saturation <20% and received 500-1000 mg of ferric carboxymaltose, were included in the study. The change in ferritin levels and transferrin saturation was calculated at 12- and 24-week follow-up. A six-minute walk test is undertaken at the first, 12-week, and 24-week follow-up visits. Results: In group 1 pulmonary hypertension patients, ferritin levels increased from 14 ng/mL to 133 and 90 ng/mL at 12- and 24-week, respectively (P <.001 for both). In group 4 pulmonary hypertension patients, ferritin levels increased from 22.1 ng/mL to 145 and 88.9 ng/mL at 12 and 24 weeks, respectively (P <.001 for both). The 6-minute walk test distances were 356, 412, and 350 m in group 1 pulmonary hypertension patients and 260, 315, and 290 m in group 4 pulmonary hypertension patients. Although the difference between baseline and 12-week 6-minute walk test was significant in both groups (P <.001 for both), this difference was lost at 24-week. Conclusion: Our study indicates that there is no difference in response to iron replacement in patients with group 1 and group 4 pulmonary hypertension patients, in terms of treatment success and functional status.