The effects of dietary protein, fasting, and refeeding on urinary characteristics of 9 captive, female white-tailed deer (Odocoileus virginianus) were studied from 23 February to 3 May 1984. Urinary sodium (Na) and potassium (K) were diminished in fasted deer after 2 and 4 weeks. Renal excretion of Na and K were lower, whereas urinary phosphorus (P) was higher in fasted deer compared to deer fed high proteinhigh energy (HPHE) diets. Urinary P excretion of the fasted deer was also greater than in a low proteinhigh energy (LPHE)-fed group. Urinary urea excretion of fasted deer was similar to that of deer fed low and high protein diets. One fasted deer died during the study and exhibited notably high excretion of urea, Na, K, and calcium (Ca). No effects of the 2 levels of dietary protein on urinary characteristics were detected. Urinary Na:C and K:C ratios were significantly correlated with Na and K intake. Urinalysis has potential as a sensitive means of monitoring the nutritional status of white-tailed deer. Data are presented as reference values for interpretation of data from deer under less controlled circumstances. J. WILDL. MANAGE. 51(4):860-864 Attempts to identify nutritional indices in white-tailed deer via blood analyses have been extensive (deCalesta et al. 1975, 1977; Seal et al. 1981; Warren et al. 1981, 1982; Card et al. 1985; DelGiudice et al. 1987a). Recently the search for indicators of nutrition in deer and other cervids has turned to urinalysis. An advantage of urinalysis stems from the critical role of kidneys and urine excretion in homeostatic mechanisms of blood. As nutritional state varies, excretion rates of specific metabolites change before differences in concentrations occur in the blood (Dale et al. 1954), thus yielding greater sensitivity as nutritional indices. Initial studies of urine indices in white-tailed deer (Warren et al. 1981, 1982; Waid and Warren 1984) and reindeer (Rangifer tarandus) (Eriksson and Valtonen 1974, Hove and Jacobsen 1975) focussed on effects of diet and season on renal urea excretion. The present study examined the effects of dietary protein, fasting, and refeeding during winter and early spring on urinary urea and several other urine characteristics not yet examined in white-tailed deer. We are grateful for financial support from the Spec. Projs. Found., Minneapolis Big Game Club; the Natl. Rifle Assoc.; the U.S. Fish and Wildl. Serv.; the Res. Serv., Veterans Adm.; the Minn. Zool. Soc.; R. Shelton; Safari Club Int.; the James Ford Bell Found.; and the Minn. Dep. Nat. Resour. We appreciate the statistical consultation of F. B. Martin and the technical assistance of M. D. Lewis, N. I. Manning, M. K. Twite, K. D. Kerr, W. J. Paul, S. H. Fritts, E. H. Stege, K. Johnson, J. Lazar, and R. J. Welters.