A field experiment was carried out during 2010/2011 and 2011/2012 seasons at the Experimental Farm of Fac. of Agric. Minia Univ. in order to investigate the response of sweet marjoram plants to compost, bio- and/or mineral NPK fertilization treatments. The obtained data revealed that the vegetative growth traits (plant height, number of branches, herb fresh and dry weight per plant/cut and /plant/season) and essential oil parameters (oil %, oil yield/plant/cut and /plant/season), as well as, chemical constituents (total chlorophylls and N, P and K %) were significantly increased due to the application of compost at different levels over those of control treatment. The maximum values were recorded at the medium level of compost (10 ton/fed.). Vegetative growth traits, essential oil productivity parameters and chemical determinations were significantly augmented as a result of using the six treatments of  bio+ and/or mineral NPK. The most effective treatment in this concern was phosphorein-Minia Azotein + 75 % NPK followed by mineral NPK (full dose) with significant differences between them in most cases. It could be recommended to supply marjoram plants with compost at 10 ton/fed. in combination with phosphorein + Minia Azotein + 75 % NPK to maximize herb and oil  productivity and their chemical constituents.