A process for manufacturing a monolithic thermal ink jet printhead (40) comprising a plurality of chambers (74) and of nozzles (56), comprises steps of (206) depositing a plurality of sacrificial layers (31), of obtaining, by means of exposure and development operations, a plurality of casts (156), of (215) applying a structural layer (107), and subsequently steps of (225) removing the casts (156) and of (226) removing the sacrificial layers (31), in order to produce a plurality of chambers (74) and nozzles (56).