Sixty-five subjects volunteered to take part in an intensive prospective investigation into the role of minor life events in precipitating episodes of minor infectious illness of the upper respiratory tract, notably 'colds'. Subjects provided daily records of desirable and undesirable events, as well as information concerning their physical health. Information was collected using standardized methods which have proven useful in recent research. Among those subjects who both provided adequate data and experienced a suitable illness episode, it was found that, relative to carefully matched control days, illness episodes were characterized by a statistically significant decrease in desirable events during the 4 days prior to symptom onset. Undesirable events were unrelated to illness episodes. This replicates and extends the most recent findings in this area, is consistent with psychoimmunological hypotheses regarding aetiological mechanisms and illustrates the promise of the new life events research based on a consideration of minor daily events.