Non-metallic inclusions in liquid samples of (I) low-carbon aluminium killed steel (0,02wpct≤C≤0,08wpct), (II) peritetic aluminium and silicon killed steel (0,09wpct≤C≤0,15wpct); (III) extra-low-carbon, aluminium killed steel (C<35 ppm) were taken from the tundish distributor of a continuous casting caster for steel plates according to a procedure that minimizes re-oxidation of steel and/or pick up of liquid slag. The samples were inspected through the following microstructural techniques: optical microscopy, electronic microscopy, and electron microprobe. Were possible to feature present inclusion in each kind of steel according to morphology, size, amout and chemical composition.