The main objective of this work was to assess the technical and economical feasibility of proteins recovery from fish meal effluents using crossflow membrane technology, namely, ultrafiltration (UF) and nanofiltration (NF). Mackerel processing effluents were pre-treated by microfiltration (MF cartridges battery of 80, 20 and 5μm pore size) followed by UF (membrane Carbosep M2, 15kDa MWCO) or NF (membrane Kerasep NanoN01A, 1kDa MWCO). A suitable treatment for the fish meal effluents consisted of a MF pre-treatment followed by UF operating at 4bar, 4m/s, natural pH and ambient temperature. UF yielded an average permeation flux of 28l/(m2 h), 1 1 1l/(hm2)=2.78×10−7 m/s. and 62% proteins rejection for a volume reduction factor of 2.3. Both membranes fully recovered their original permeabilities through an acidic/basic washing cycle. The economic assessment of proteins recovery from fish meal effluents by UF was accomplished for a production of 544ton/yr of fish meal (66% protein content), yielding a net present worth of 160×103 US$, interest rate of return of 17% and payback time of 8 years.