Prescriptions for short-acting β2-agonists (SABAs) and oral corticosteroids recorded in a primary care database were used as markers of asthma control. Drug use in the 6 months before and after step-up in treatment from inhaled corticosteroids [ICs; total daily dosage of ≤1000 µg beclomethasone dipropionate (BDP) or equivalent] to either salmeterol/fluticasone propionate combination (SFC) or concurrent BDP and long-acting β2-agonists (LABAs) given in separate inhalers was compared. After step-up, the calculated median number of doses of SABAs prescribed fell by 100 in the SFC group (n = 211) but was unchanged with BDP + LABA (n = 377, p < 0.0001), and fewer patients in the SFC group were prescribed oral corticosteroids (13.7 vs. 20.7%, p = 0.036). Other measures of SABA use after step-up indicated lower use in the SFC group. In clinical practice, adding LABA to IC therapy by using a combination inhaler produces significantly better asthma control than administering the drugs in separate inhalers.