The women's javelin throw event at the 2004 World Junior Championships in Athletics was held in Grosseto, Italy, at Stadio Olimpico Carlo Zecchini on 13 and 15 July.
| Gold | Vivian Zimmer | |
| Silver | Annika Suthe | |
| Bronze | Annabel Thomson |
15 July
| Rank | Name | Nationality | Attempts | Result | Notes | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | 6 | ||||||||
| align=left | align=left | 58.24 | 58.50 | 54.70 | 58.21 | 54.78 | 58.19 | 58.50 | |||||
| align=left | align=left | 57.13 | x | 52.08 | 54.38 | 54.81 | 57.15 | 57.15 | |||||
| align=left | align=left | | 53.26 | 52.38 | 51.04 | 54.06 | 53.64 | 56.01 | 56.01 | ||||
| 4 | align=left | align=left |  | 51.44 | 52.78 | 51.02 | 50.69 | 52.89 | 54.77 | 54.77 | |||
| 5 | align=left | align=left |  | 54.44 | 52.60 | 51.93 | 51.84 | 50.06 | 53.77 | 54.44 | |||
| 6 | align=left | align=left |  | 43.77 | 49.64 | 54.05 | 49.93 | x | x | 54.05 | |||
| 7 | align=left | align=left |  | 52.70 | 48.63 | 49.06 | 49.61 | 48.26 | 49.99 | 52.70 | |||
| 8 | align=left | align=left | | 52.59 | 52.67 | 51.46 | 48.87 | 51.13 | 51.30 | 52.67 | |||
| 9 | align=left | align=left | | 52.25 | 50.56 | 49.44 | 52.25 | ||||||
| 10 | align=left | align=left |  | x | 49.03 | 51.66 | 51.66 | ||||||
| 11 | align=left | align=left |  | 51.16 | x | 47.07 | 51.16 | ||||||
| 12 | align=left | align=left |  | 50.24 | x | 51.01 | 51.01 | ||||||
13 July
| Rank | Name | Nationality | Attempts | Result | Notes | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | ||||||||
| 1 | align=left | align=left | | 49.51 | 49.00 | 55.51 | 55.51 | Q | ||
| 2 | align=left | align=left | | 54.54 | - | - | 54.54 | Q | ||
| 3 | align=left | align=left | 53.45 | - | - | 53.45 | Q | |||
| 4 | align=left | align=left | | 53.13 | - | - | 53.13 | Q | ||
| 5 | align=left | align=left | | 51.52 | 48.44 | 52.32 | 52.32 | Q | ||
| 6 | align=left | align=left | | 46.39 | 51.95 | 47.46 | 51.95 | q | ||
| 7 | align=left | align=left |  | 49.23 | 45.32 | x | 49.23 | |||
| 8 | align=left | align=left | | x | 49.12 | 45.50 | 49.12 | |||
| 9 | align=left | align=left |  | 48.77 | 48.19 | 46.87 | 48.77 | |||
| 10 | align=left | align=left | 42.17 | 48.73 | 48.52 | 48.73 | ||||
| 11 | align=left | align=left |  | 40.25 | 47.56 | 40.35 | 47.56 | |||
| 12 | align=left | align=left | 47.36 | x | 45.14 | 47.36 | ||||
| 13 | align=left | align=left | 43.93 | x | 43.15 | 43.93 | ||||
| 14 | align=left | align=left | 41.83 | x | x | 41.83 | ||||
| Rank | Name | Nationality | Attempts | Result | Notes | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | ||||||||
| 1 | align=left | align=left | 52.23 | 54.13 | - | 54.13 | Q | |||
| 2 | align=left | align=left | | x | 52.30 | - | 52.30 | Q | ||
| 3 | align=left | align=left | | 50.45 | 51.92 | 52.11 | 52.11 | q | ||
| 4 | align=left | align=left | | 50.71 | 48.53 | 51.65 | 51.65 | q | ||
| 5 | align=left | align=left | | 50.63 | x | 51.12 | 51.12 | q | ||
| 6 | align=left | align=left | | 49.89 | 49.46 | 49.78 | 49.89 | q | ||
| 7 | align=left | align=left | | 49.51 | 38.01 | x | 49.51 | |||
| 8 | align=left | align=left | | 48.38 | 47.62 | 48.85 | 48.85 | |||
| 9 | align=left | align=left |  | x | 47.91 | x | 47.91 | |||
| 10 | align=left | align=left |  | 39.08 | 47.81 | 47.04 | 47.81 | |||
| 11 | align=left | align=left | 46.05 | 46.15 | 46.88 | 46.88 | ||||
| 12 | align=left | align=left |  | 43.94 | 43.89 | 44.65 | 44.65 | |||
| 13 | align=left | align=left | | x | 43.95 | 41.49 | 43.95 | |||
| 14 | align=left | align=left |  | x | 42.27 | 42.89 | 42.89 | |||
| 15 | align=left | align=left | 42.71 | 42.66 | 42.38 | 42.71 | ||||
According to an unofficial count, 29 athletes from 22 countries participated in the event.