The Patek Philippe Annual Calendar reference 5035, launched in 1996, is a self-winding watch in a 37 mm case of precious metal, with a moon phase and apertures showing the day, date and month. Its calendar recognises the different month lengths and needs correcting only once a year, at the end of February. The watch has a sapphire case back and a rotor in gold.

The annual calendar was a new complication, introduced as a more practical alternative to the perpetual calendar, and Patek patented the mechanism. The 5035 was the first watch to carry it, and the idea has since been copied across the industry.

Collectors value the 5035 as the origin of a now common complication and a well-balanced dress watch, and the earlier gold versions are especially sought. The 5035 was replaced by later annual calendar references, and the model is no longer made.