A better understanding of population dynamics leads to more informed wildlife management decisions. Investigations of mortality rates and their causes for maturing white-tailed deer (Odocoileus virginianus) are lacking in the Coastal Plain of the Southeast. We captured 36 (18 male and 18 female) fawns with rocket nets and radio-collared them on Westvaco's North Whitener tract in Jasper County, South Carolina, from October through December 1992. We radio-tracked these deer during the 1993 calendar year to investigate mortality rates in a coastal area under a quality deer management program. Calendar year mortality rates, estimated with the Kaplan-Meier product limit method, were 0.389 (SE = 0.115) for females and 0.410 (SE = 0.119) for males. Sex-specific survival functions did not differ within the year (P = 0.906) or within either age-period analyzed (fawn period, 1 Jan-31 May, P = 0.300; yearling period, 1 Jun-31 Dec, P = 0.229). However, sources of mortality appeared to differ by sex-class. All 7 female mortalities were from non-hunting mortality factors, whereas 5 of 7 male mortalities were attributable to off-site hunter harvest of dispersing yearling bucks. Non-hunting mortality (9 of 14) was highest from January to May (7 of 9), which coincided with a time of heavy flooding. Hunting mortality (5 of 14) occurred from October to December as bucks dispersed from the study site. The maturing segment of the study site deer population (0.5 year olds to 1.5 year olds) is primarily controlled by non-hunting mortality in association with seasonal stress and off-site hunting mortality associated with fall movement patterns.