Abstract: The present invention relates generally to a method of diagnosing, predicting or monitoring the development or progress of heart failure in a mammal and, more particularly, to a method of diagnosing, predicting or monitoring the development or progress of congestive heart failure in a mammal. The present invention contemplates a method for detecting heart failure by screening for the systemic presence of pulmonary surfactant protein in a subject. The present invention further provides a method for diagnosing or monitoring conditions associated with or characterised by the onset of heart failure, in particular congestive heart failure. Also provided are diagnostic agents useful for detecting one or more surfactant proteins.