Chronic pulmonary aspergillosis (CPA) is a condition caused by the ubiquitous fungus Aspergillus fumigatus in non-immunocompromised individuals. Numerous underlying conditions have been associated with CPA. Details of the underlying conditions of 126 CPA patients attending our tertiary referral clinic from all over the UK were extracted from the clinical notes, and the distribution of these underlying conditions was analysed. For those with several underlying pulmonary conditions, one was nominated as the primary condition. Many patients presented with multiple underlying conditions, and a total of 232 underlying conditions were identified for the 126 patients. Previous classical tuberculosis and non-tuberculous mycobacterial infection were the most common primary underlying conditions (15.3% and 14.9%, respectively). Others included allergic bronchopulmonary aspergillosis (ABPA), chronic obstructive pulmonary condition (COPD) and/or emphysema, pneumothorax and prior treated lung cancer. Some conditions were found more often as one of multiple underlying conditions, while others were found only as secondary underlying conditions. Tuberculosis, non-tuberculous mycobacterial infection and ABPA remain the predominant risk factors for development of CPA, with COPD, prior pneumothorax or treated lung cancer also relatively common among our referrals. Many patients have multiple underlying pulmonary conditions. CPA should be considered when upper lobe cavitary or fibrotic disease and systemic symptoms are present in those with lung disease.