Introduction: A 2007–2008 report from the Australian Bureau of Statistics estimated that 61.4% of Australians are overweight or obese. Therefore, the aim of the present investigation was to further characterize the relationship between body mass index (BMI: kg • m−2) and several prevalent disease states. Methods: The Population Research Laboratory at Central Queensland University conducted a Computer-Assisted-Telephone-Interview survey (N = 1289) during October–November 2010. Respondents were 18 years of age or older that could be contacted by a direct-dialed, land-based telephone service. A computer program containing telephone contact details was used to select, with replacement, a simple random sample of respondents. Separate bivariate logistic regression models were used to examine the associations between BMI (normal weight: 18.5–24.9; overweight: 25.0–29.9; obese: ≥30.0) and self-reported health information relating to disease states. For all analyses, normal weight was used as the reference group and significance was set at (p < 0.05). Data are presented as raw and weighted odds ratios which were adjusted for age and geographic location. Results: Raw and weighted data yielded similar results for the increased presentation of diabetes (obese: 1.94, CI: 1.19 to 3.19; 2.09, CI: 1.17 to 3.71), arthritis (obese: 1.62, CI: 1.14 to 2.30; 1.63, CI: 1.10 to 2.42), and heart disease (obese: 1.75, CI: 1.06 to 2.89; 1.98, CI: 1.10 to 3.56), respectively. In this regard, being overweight or obese was found to significantly increase the presentation of hypertension (raw data: overweight: 1.75, CI: 1.27 to 2.41, obese: 2.72, CI: 1.95 to 3.79; weighted data: overweight: 1.85, CI: 1.29 to 2.66, obese: 3.63, CI: 2.52 to 5.23), hypercholesterolemia (raw data: overweight: 1.61, CI: 1.14 to 2.30, obese: 2.02, CI: 1.40 to 2.91; weighted data: overweight: 1.93, CI: 1.30 to 2.86, obese: 2.32, CI: 1.54 to 3.50), and osteopenia/osteoporosis (raw data: overweight: 1.99, CI: 1.07 to 3.70, obese: 2.33, CI: 1.23 to 4.40; weighted data: obese: 2.66, CI: 1.27 to 5.57). Raw data found an increase in BMI to increase the presentation of depression (obese: 1.52, CI: 1.06 to 2.20) and hyperlipidemia (overweight: 2.32, CI: 1.02 to 5.27; obese: 3.03, CI: 1.32 to 6.93). BMI did not influence the presentation of cancer or thyroid disorder. Discussion: The link between BMI and disease risk is concerning, particularly with obesity rates in Australia on the rise. Health education programs geared towards children and younger adults must be established in an attempt to reduce disease prevalence.