Prescribing patterns in chronic obstructive pulmonary disease (COPD) are often inconsistent with published guidelines. This retrospective, observational study utilised data from the Optimum Patient Care Research Database to examine the changes in COPD prescribing patterns over time and to identify predictors of physician treatment choice for patients newly diagnosed with COPD. Initial therapy was defined as the treatment(s) prescribed at or within 1 year before COPD diagnosis. Changes over time were assessed in three cohorts based on the date of diagnosis: (1) 1997-2001; (2) 2002-2006; and (3) 2007-2010. Factors affecting the odds of being prescribed any initial therapy or any initial maintenance therapy were identified by univariable and multivariable logistic regression. The analysis included 20,154 patients, 45% of whom were prescribed an initial regimen containing an inhaled corticosteroid (ICS), whereas 28% received no initial pharmacological treatment. Prescribing of ICS monotherapy decreased over time, as did the proportion of patients receiving no therapy at or within 1 year before diagnosis. Comorbid asthma, a high exacerbation rate, increased symptoms and poor lung function each increased the likelihood of being prescribed any initial therapy or initial maintenance therapy; comorbid asthma and an annual rate of ⩾3 exacerbations were the strongest predictors. In conclusion, our analyses revealed major differences between actual prescribing behaviour and guideline recommendations for patients with newly diagnosed COPD, with many patients receiving no treatment and large numbers of patients receiving ICS-containing regimens. Predictors of initial therapy were identified.