[Truncated abstract] Asthma genetic studies have identified many genes that contribute to the pathogenesis of asthma and related variables. Members of the secretoglobin family appear to play an important role in controlling airway inflammation but they have received relatively little attention in asthma genetic research. In this thesis, I have investigated the genes of two members of the secretoglobin family (16 kDa Clara cell secretory protein (CC16) and secretoglobin 3A2 (SCGB3A2)) that are expressed at high levels in the airways and are important anti-inflammatory agents. The overall aim of these studies was to investigate the genetic variability of the CC16 and SCGB3A2 genes and their influence on airway inflammatory disease. The main hypothesis was that genetic variability in the genes for CC16 and SCGB3A2 exert an influence on airway inflammatory disease. Three populations were investigated: (1) a paediatric case control population (n=99), (2) an unselected birth cohort followed longitudinally at ages 1 month (n=244), six (n=123) and 11 years (n=195) and (3) an unselected Aboriginal Australian population (n=251). The case-control population was screened for novel DNA sequence variants in the CC16 promoter and the SCGB3A2 5’UTR and exons. No novel sequence variants were identified in the CC16 promoter and two were identified in the SCGB3A2 5’UTR (G- 811A and G-205A). A single nucleotide polymorphism previously identified in the CC16 gene (A38G) and the two polymorphisms identified in the SCGB3A2 gene were genotyped in both unselected populations. Genotype/phenotype associations were identified with adjustment for potential confounders such as age, gender, height and maternal tobacco smoking, where appropriate. This was due to the contribution of these factors to the aetiology of asthma, atopy and related phenotypes. All three polymorphism frequencies were significantly different between these two ethnically diverse populations