The changes in the hemolymph proteome of mygalomorph Brachypelma albopilosa females were examined for the first time in relation to their developmental stage (subadult and adult period). Seven distinct subunits of hemocyanin (a, b, c, d, e, f, and g chains), as well as actin were clearly identified and their sequence partly characterized using a combination of one- and two-dimensional gel electrophoresis and mass spectrometry. The different structures determined along with possible post-translational modifications may reflect a role of hemocyanin in molting, immunity, and reproduction. In addition, despite no precise identification, additional peptide sequences from eight protein bands (four bands >200 kDa and four bands in the 95-200 kDa mass range) were determined. As reported in other spider species, the putative corresponding structures are the coagulogen protein and/or lipoproteins (HDL-1, HDL-2, VHDL) for which quantitative differences between adult and subadult individuals could be related to the molting process and/or cuticle lipid and protein composition according to the developmental stage.