Marjolin's ulcer is a rare and often overlooked diagnosis which can be encountered by a variety of specialities. Majority of the literatures describe long latency period of 11 to 75 years. The authors present two unusual cases of rapid progression to Marjolin's ulcer in patients with previously negative biopsy 8- and 10-month prior. This highlights the importance for clinicians to have a high degree of suspicion when encountered with any non-healing wound, especially one who's symptomatology and morphological features have undergone an acute change. Even with previous negative biopsy, patients should still be followed-up closely and clinicians should not hesitate to perform re-biopsy if the suspicion arises.