Background: Preoperative neoadjuvant chemotherapy with cisplatin plus 5-FU (CF) is the standard treatment for resectable esophageal cancer (EC). Docetaxel plus CF (DCF) is also a promising preoperative treatment; however, a high frequency (5%-30%) of febrile neutropenia (FN) has been reported in patients (pts) receiving DCF, and elderly pts reportedly have a high risk of FN. The use of primary prophylactic pegfilgrastim (PG) on day 3 of DCF in resectable EC pts might prevent FN. We conducted a retrospective review to assess the efficacy of primary prophylactic PG administration on day 3 of preoperative DCF in elderly pts with resectable EC. Methods: EC pts who had received preoperative DCF between 2009 and 2021, were ≥70 years old, and had adequate organ functions and an adequate PS were eligible for this retrospective study. Pts were assigned to receive either PG-containing DCF (day3 prophylactic PG: D3PG) or standard DCF (non-prophylactic PG: NPG). Three courses of DCF (DTX [day 1]: 70 mg/m², CDDP [day 1]: 70 mg/m², 5-FU [continuous infusion on days 1-5]: 750 mg/m², every 3 weeks) were planned, and antibiotic prophylaxis was mandatory on days 5-15 in each group. In the D3PG group, PG was administered subcutaneously on day 3. We retrospectively evaluated the relative dose intensity (RDI), histopathological efficacy, and adverse events (CTCAE ver5.0). Results: A total of 52 pts (D3PG, 17; NPG, 35) with a median age of 72 years were identified. The PS (0/1/2) and clinical stage (I/II/III/IVB [only supraclavicular lymph node]) were 10 (58.8%)/5 (29.1%)/2 (11.8%) and 0/1 (5.9%)/10 (58.8%)/6 (35.4%) in the D3PG group and 20 (57.1%)/15 (42.9%)/0 and 2 (5.7%)/5 (14.3%)/24 (68.6%)/4 (11.4%) in the NPG group, respectively. Three pts discontinued treatment because of toxicity (FN and nausea in D3PG and FN and diarrhea in NPG) and progression in each group, and all the pts underwent surgery. The RDIs (DTX/CDDP/5-FU) were 0.870/0.862/0.871 in the D3PG group and 0.833/0.829/0.830 in the NPG group. Five (29.4%) pts in the D3PG group and 10 (28.6%) in the NPG achieved a pCR. The common grade ≥3 adverse events (D3PG/NPG) were leukopenia (17.6%/51.4%), neutropenia (11.8%/71.4%) and FN (5.9%/20.0%). Conclusions: The use of primary prophylactic PG on day 3 of preoperative DCF improved the treatment safety treatment in elderly pts with resectable EC. No significant differences in treatment efficacy were seen between the D3PG and NPG groups despite the higher number of pts with a worse general condition or more advanced disease in the D3PG group than in the NPG group.