This study is a randomized, prospective, active-controlled, single-center, open label, dose-ranging clinical trial of TIV (Fluzone®) administered to healthy 18-to-49 year old adults who did not receive 2003-2004, 2004-2005 and 2005-2006 influenza vaccine. Subjects will be randomized to one of 7 groups (4 intramuscular and 3 intradermal) to compare the immunogenicity and safety of different concentrations of the standard Fluzone® administered intradermally using the Mantoux technique to that of standard Fluzone® administered intramuscularly. The primary objective of the study is to compare the immunogenicity of injected Fluzone® across different dose levels and different routes of administration. The secondary objectives are to describe the number and proportions of subjects in each group experiencing any injection site or systemic symptoms and the proportion of subjects who experience moderate-to-severe symptoms post vaccination. Approximately 31 subjects per group (217 in total) will be enrolled with each group determined by dose and route of administration of vaccines. Subjects will be observed in the clinic for at least 30 minutes after immunization and will maintain a memory aid to record daily oral temperature and any systemic and local reactions for 7 days after the day of immunization. Subjects will be contacted by phone between 8 to 12 days after immunization to review their 7-day memory aid, including the assessment of their recorded daily oral temperature, any local or systemic reactions, and the occurrence of any other AEs and SAEs. Subjects will return at 28 (+/- 3) days after immunization to assess the occurrence of unsolicited AEs and SAEs and complete an acceptability and functional skill questionnaire. Serum for immunogenicity evaluations will be obtained prior to the first vaccination and approximately 28 (+/- 3) days post vaccination. The 2005-2006 formulation will be used for all seven groups.