AIM: This analysis investigates incidence and time course of rash in the EURTAC study. MATERIALS & METHODS: Patients with EGFR mutation-positive non-small-cell lung cancer were randomized 1:1 to receive once daily erlotinib or 3-weekly cycles of chemotherapy. RESULTS: Of the 86 erlotinib-treated patients, 71 reported rash. Median time to first rash appearance was 0.7 months. Most patients (n = 65) had the same or lower grade rash at final assessment compared with initial assessment. Of the 21 patients with decreased rash grade between initial and final assessments, 61.9% received no erlotinib dose modification, 42.8% had no concomitant rash treatment. CONCLUSION: Most rash cases were mild, occurred within 1 month of erlotinib treatment, and rapidly improved without the need for erlotinib dose alterations.