Aims: To evaluate prescription of prophylactic treatment before and after consultation in a neurology headache clinic and to determine predictors for prophylactic treatment and clinical improvement. Methods: Clinical records of consecutive patients assessed in a neurologic headache clinic in Portugal and diagnosed with acute or chronic migraine and/or tension-type headache were assessed. Prescription of prophylaxis before and after the first visit to the clinic were compared. Logistic regression was used to evaluate predictors of the need for therapeutic intervention and clinical improvement. Results: Among 409 patients (86.8% women; mean age 41.6 years), 315 (77%) had indication for prophylaxis, and 70 (22%) of these patients were already on prophylactic treatment. Among the 265 patients with information for follow-up, prophylactic treatment was added in 178 (67.2%), and there was a significant change in the number of treated patients between the first and second visits. Ongoing treatment was switched or the dose increased in 21 patients. Multivariate logistic regression revealed that women (odds ratio [OR] = 2.09, 95% confidence interval [CI] 1.1 to 3.97] and patients with medication overuse headache (MOH) (OR = 6.97, 95% CI 1.60 to 30.39) were more likely to need therapeutic intervention, whereas patients referred from the emergency room were less likely to need it (OR = 0.44, 95% CI 0.22 to 0.89). Of the 265 patients, 185 (69.8%) had improved at a follow-up. Having prophylactic treatment at the time of the second visit was associated with improvement (OR = 2.39, 95% CI 1.23 to 4.63; P = .01). Conclusion: Women and medication overuse headache patients were more likely to need therapeutic intervention. However, only a minority of patients with treatment indication were treated before their first visit to the headache clinic. Prophylaxis prescription was associated with clinical improvement at follow-up. Keywords: chronic headache, headache, migraine, outpatient clinic, prophylaxis, referrals