Thick-film and LTCC (Low Temperature Cofired Ceramic) technologies are now recognised as valid platforms for the fabrication of novel devices at the mesoscale for sensor, actuator, fluidic, electrical and packaging applications. In these fields, they allow the fabrication of sensitive, yet robust and cost effective devices. This work reviews and comments the different available structuration techniques, with an emphasis on sensor technology and on structuration methods based on sacrificial layers. This is exemplified through various sensors and related devices developed at our laboratory and elsewhere. Processing conditions are also discussed, with the aim of obtaining useful and reproducible sacrificial materials. Key words: sensors, thick-film, LTCC, 3D structuration, sacrificial layers, processing.