Aim: This study was conducted to evaluate the antimicrobial activities of seed extract of Phoenix dactylifera. Study Design: Extraction of active ingredients of Phoenix dactylifera seeds using methanol and its effects on selected clinical isolates and isolated strains of E. coli. Place and Duration of Study: `Department of Phatrmaceutical Microbiology and Biotechnology, Faculty of Pharmaceutical, University of Nigeria, Nsukka between march 2017 and October 2018. Methodology: The seed of phoenix dactylifera were washed thoroughly to get rid of any adhering date flesh, air dried and ground. The ground powders were subjected to extraction by cold maceration using methanol. Preliminary sensitivity test was carried out against eight microorganisms, namely: Pseudomonas aeruginosa, E. coli, Enterococcus, Klebsiella, Staph. spp, Salmonella spp, Bacillus sp and Candida albicans using agar diffusion method. Antimicrobial susceptibility tests were carried out on isolated strains of E. coli from urine samples using agar diffusion method. The minimal inhibitory concentrations of crude methanol extract of seeds of Phoenix dactylifera were determined using agar diffusion method. The phytochemical analysis was conducted to determine the secondary metabolites. Results: The preliminary sensitivity test performed shows that the crude methanol extract of date seed were sensitive against all organisms tested. The active ingredients of the extract showed activities against all strains of E. coli tested though their zones of inhibition vary (18-21mm). The minimum inhibitory concentration (MIC) value ranges from 10-19.9 mg/ml. The phytochemical analysis of crude methanol seed extract of P. dacterifera indicated the presence of alkaloids, flavonoids, tannins, carbohydrates, proteins, reducing sugar, sterols and Terpenes, Anthraquinone glycosides. Conclusion: The present study provides the scientific information about Phoenix dactylifera seed activity.