This invention relates generally to filtration cassettes, and, more particularly to methods of fabricating cross-flow filtration cassettes. Cassettes of the invention are characterized, in part, by an internal porting (e.g., manifolding) feature which eliminates the need for a separate step to seal individual components prior to assembly of the filtration cassette. Filtration cassettes of the present invention can be manufactured from conventional membrane and flow screen components and can utilize both injection molding and vacuum assisted resin transfer molding fabrication processes.