Malignant lesions of the skin are common. Patients who develop squamous cell carcinoma and malignant melanoma often have recognizable precursor conditions. A few skin lesions resemble malignancies. Lesions that are growing, spreading or pigmented, or those that occur on exposed areas of skin are of particular concern. Knowing the similarities and differences between these lesions allows the primary physician to make a diagnosis in most cases by simple inspection and palpation. When in doubt, it is appropriate to perform an excisional biopsy of small lesions or punch biopsy of larger lesions. Removal of premalignant lesions will reduce the occurrence of malignant disease. Almost all skin cancers can be cured by early excision or destruction. For these reasons, physicians should be aware of the risk factors for skin cancer, educate patients about risk reduction and include skin inspection for premalignant and malignant lesions as a part of routine health maintenance examinations.