In the present paper, the valorisation of two residues: Posidonia oceanica and date palm rachis was investigated. First, their chemical composition was studied and showed that they present amounts of holocellulose, lignin and cellulose similar to those encountered in softwood and hardwood. Extractives in different solvents and ash contents are relatively high. Moreover, ash composition assessment showed that silicon is the major component (17.7%) for A oceanica. The high ash quantity and the low DP (about 370) may be considered as serious disadvantages of A oceanica, in the pulping and papermaking context. Oppositely, the properties of rachis date palm and those of the ensuing pulp, obtained from a classical soda-anthraquinone cooking, demonstrated the Suitability of this agricultural by-product for papermaking. Preliminary tests conducted on unrefined pulp suspensions and handsheets from date palm rachis in terms of freeness, Water Retention Value and mechanical properties allowed confirming the good quality of date palm rachis fibres. (C) 2009 Elsevier Ltd. All rights reserved.