BACKGROUND With the increasing knowledge that estimation of glomerular filtration rate (GFR) from serum creatinine (Scr) has limited value, researchers have developed new equations based on serum cystatin C (Cys C). OBJECTIVE To compare the performance of serum Cys C and Cys C-based GFR equations to Scr and Scr-based GFR equations. METHODS A Medline literature search for studies in English. RESULTS Fourteen studies in kidney transplant patients and 29 in patients with native kidney disease were identified. 70% of studies on transplants favored Cys C over Scr while 60% favored serum Cys C over Scr in patients with native kidney disease. Three studies in transplant patients and 6 in patients with native kidney disease compared the performances of Cys C- and Scr-based equations. 70% of the studies performed on transplantation favored Cys C, while 85% the studies performed in native kidney diseases showed superiority of Cys C-based equations. CONCLUSIONS A large number of studies favor Cys C over Scr for the estimation of GFR. Still, many reports show no superiority of Cys C over Scr. Consistent with this, more studies are needed to study the performance of Cys C-based GFR equations.