The burden of asthma attributable to occupational exposures is significant. A better evaluation of markers of asthma and rhinitis in occupational settings may help reduce the frequency of occupational asthma (OA) and rhinitis (OR). This publication reviews articles published in 2008 and 2009 to provide an update on aspects related to markers of asthma and rhinitis. Markers derived from occupational exposure assessment, questionnaires, clinical data, and noninvasive tests such as functional tests or measures of serum antibodies are used to develop prediction models for the likelihood of OA and OR development. Findings from prospective studies highlight the course of preclinical signs and markers of airway inflammation in the natural history of OA and OR. Airway inflammation, evaluated by quantification of cells and mediators in induced sputum or nasal lavage and by exhaled nitric oxide, is associated with OA and OR; however, the sensitivity and specificity of these means, especially exhaled nitric oxide, have not been sufficiently assessed.