The plant material in the current study in two successive seasons of 2007 and 2008 was guava fruits harvested from fruiting trees pre-harvest, 10 days to harvest date, sprayed with tap water (TW) to serve as control or with vitamin B₁₂ solution either at 0.3 or 0.6 mg.L ^-1 The harvested fruits were immediately transported to the laboratory, thoroughly washed with tap water and soap to remove impurities on the fruit surfaces. These fruits were cold stored for 30 days at 8±1^oC and 80-85% RH after soaked in tap water (control) or in Ca Cl₂ solution either at 1.5 or 3.0% for 15 min. Fruits during cold storage period were subjected to periodical measurements of 3 physical and 6 chemical characteristics at 6-day-intervals to measure changes of these characteristics throughout cold storage period. The obtained results revealed that factors affected the behavior of guava fruit characteristics during cold storage period were differed due to the measured characteristic. Fruits of the “T9"treatment (pre-harvest sprayed trees with vitamin B₁₂ solution at 0.6 mg.L^-1 plus post-harvest soaked the harvested fruits in Ca Cl₂solution at 3.0% for 15 min as well as stored at 8±1^oC and 80-85% RH) recorded the best quality at the end of storage period. They measured the highest firmness, vitamin C, total soluble sugars and total phenols along with the least fruit weight loss%. On the other hand, the least acidity% found in fruit juice of “T4" treatment (Pre-harvest sprayed trees with vitamin B₁₂ at 0.3 mg.L^-1). The same treatment plus soaked the harvested fruits in Ca Cl₂ at 1.5% or 3.0% (T5 and T6) were the best ones to keep TSS% and TSS/acid ratio at the higher level at the end of cold storage period.