Maintaining the health of senior horses requires careful attention, particularly when it comes to parasite control. Worming - or deworming - is a crucial aspect of equine health care, and specific considerations are required for horses over 15 years of age. Factors such as the horse's immune status, geographic location, seasonal parasite prevalence and underlying health conditions play a vital role in creating an effective worming plan. In this article we outline some key factors to take into consideration to help manage worm burdens in older horses.