Purpose: The objective of the this study is to assess the quality of twenty six formulations of three essential drugs (ten brands of paracetamol tablets, nine brands of ciprofloxacin hydrochloride tablets, and seven brands of amoxicillin trihydrate capsules) marketed in Palestine. As well, use and validate an analytical method which will be easy to handle, accurate, simple and inexpensive for assay of content of ciprofloxacin hydrochloride in the tablets and amoxicillin trihydrate in the capsules. Method: The quality of paracetamol tablets was assessed through evaluation of identification, diameter, thickness, uniformity of weight, friability, hardness, disintegration, dissolution as well as assay of content of active ingredient, while for ciprofloxacin hydrochloride tablets and amoxicillin trihydrate capsules evaluation through identification using iron (III), uniformity of weight, disintegration, dissolution and assay of content of active ingredient using spectrophtometric method. Results: All brands of paracetamol tablets passed the British Pharmacopoeia 2005 standards for identification, uniformity of weight, friability, disintegration, dissolution tests and assay of content of active ingredient. All ciprofloxacin hydrochloride tablets and amoxicillin trihydrate capsules brands passed the identification test by using iron (III) through comparing the resulted color from brands with the color which resulted from the pure active substance. All brands of ciprofloxacin hydrochloride tablets and amoxicillin trihydrate capsules passed British Pharmacopoeia 2005 standards for uniformity of weight and disintegration tests, and passed United States Pharmacopoeia 30 standard for dissolution test except one brand of ciprofloxacin hydrochloride tablets failed the dissolution test. Six of nine brands of ciprofloxacin hydrochloride tablets and one of seven brands of the amoxicillin trihydrate capsules do not comply with British Pharmacopoeia 2005 standard for assay of content of active ingredient. Conclusion: All brands of paracetamol tablets, only three of nine brands of ciprofloxacin hydrochloride tablets and six of seven brands of amoxicillin trihydrate capsules meet quality specifications in Pharmacopoeia. Reaction of ciprofloxacin hydrochloride and amoxicillin trihydrate with iron (III) is sensitive, selective, simple, efficient, inexpensive, and rapid for identification, also the spectrophotometric method used in assay of content of active ingredient of ciprofloxacin hydrochloride tablets and amoxicillin trihydrate capsules is simple, inexpensive, easy to use and could be used in routine monitoring especially in the absence of high technology equipments. In general this study shows the needing for more market monitoring of all available brands of all drugs on the Palestinian drug market.