The present study was carried out to produce low-fat beef burger using oat at 1.5, 2.5 and 4%as fat-replacer and some natural additives to improve flavor and as preservative materials. Thyme (0.75%), rosemary (0.75 %) and mixture of thyme (0.375 %) + rosemary (0.375 %) were added to the suggested low-fat beef burger formulae. A control sample without any of these additives was used. All samples were stored at -20ْ C for three months. At zero time and during storage period, burger samples were subjected to one of the following cooking methods: a) Grilling of raw burger. b) Grilling of partially cooked ( by microwave ) burger. Organoleptic as well as microbiological tests were performed. Results showed that the presence of oat at 2.5% improved tenderness, texture, chewing and overall-acceptability of the investigated samples. Thyme in the micro waved-grilled beef burger samples showed significant deterioration in chewing and overall-acceptability. Grilling or Microwave cooking of burger followed by grilling caused sharp decrease in total microbial count and complete elimination of E. coli and St. aureus. During frozen storage, samples with thyme contained lower microbial counts than those samples containing mixture of thyme and rosemary.