Squamous cell carcinoma (SCC) of the head and neck is the sixth most frequently occurring cancer in the world. Globally, it accounts for 3-5% of all the cancers globally. There is a vast difference in the incidence of oral cancer in different regions of the world. The overall 5-year survival rate for patients with head and neck SCC is observed to be the lowest for major cancers. Despite therapeutic and diagnostic progress in oncology in past few decades, the prognosis of intraoral SCC remains poor. Current clinical practice in oncology has a growing impetus on early diagnosis, proper prognostication and screening for malignancy in asymptomatic group. With the technological advancement, research have led to the identification of numerous tumor biomarkers that are prognostic markers and predictive markers. Also, these can be used for screening and early detection of Cancer, Determining the Cancer prognosis, Determining the Effectiveness & Monitoring of Treatment and for detection of recurrence. The purpose of this book was to focus on the tumor markers or predictive indicators available, in general. Also, the prospects and research for ideal tumor marker has been discussed.