Kidney disease is very common in patients with cancer. Nephrologists are vital members of the multidisciplinary care team for these patients. Given the high prevalence of comorbidities in patients treated for active malignancy, it is not surprising that these individuals frequently develop renal diseases that are common among other hospitalized patients, such as those arising from sepsis, hypotension or use of nephrotoxic agents (e.g. radiocontrast or antimicrobial agents). The role of the nephrologist in these cases differs little with respect to the presence or absence of cancer. On the other hand, there are several renal syndromes that are unique to patients with cancer, being caused either by the cancer itself or by its treatment. These syndromes are reviewed here. In addition, patients who are receiving chemotherapy often require dialysis for either acute or chronic kidney disease. Unfortunately, there is very little information on the clearance characteristics of most chemotherapeutic agents. In cancer patients with renal disease, both the timing of administration and the dose-adjustment of chemotherapy must rely on clinical experience and close clinical observation.