Persistent pulmonary hypertension (P-PH) after mitral valve replacement (MVR) leads to an increased risk of morbidity and mortality. We sought to determine which factors were involved in its occurrence. Patients undergoing MVR for a 3-year period were collected in a retrospective way. We excluded those with an available follow-up shorter than 3 months. Sample size was 111 patients. PH was diagnosed if systolic pulmonary artery pressure (sPAP) estimated by Doppler echocardiography was >40 mmHg. Clinical, echocardiographic, and surgical factors were analyzed. P-PH was present in 42.3 % of patients after 12.6 months of mean follow-up. P-PH was more frequently observed in elderly and female patients, in those with severe degrees of PH before surgery, and significant tricuspid regurgitation (TR). On multivariable analysis, significant TR (OR 1.739; p = 0.01) and more severe degrees of PH before surgery (OR 1.761; p = 0.03) were significantly associated with the presence of P-PH after MVR. Surgical factors related to P-PH were prosthesis size and tricuspid annuloplasty: no need for the performing of tricuspid annuloplasty (OR 0.345; p = 0.025) and the implantation of a smaller prosthesis (OR 0.656; p = 0.004) were related to higher rates of P-PH after MVR. MVR was associated with high prevalence of P-PH after mid-term follow-up. Both PH and significant TR before surgery were associated with P-PH. Our data point out that MVR should be planned before the development of PH and greater TR. Smaller prosthetic size is also a risk factor for P-PH and bigger prostheses are desirable when possible.