We report our studies on electrical properties of Y‐Ba‐Cu‐O test devices and circuits fabricated using a laser‐writing patterning technique. The patterning procedure is noninvasive, does not require a patterning mask, and does not contaminate nor damage the surface of patterned films. Our laser‐written, oxygen‐rich lines (typically 4–100 μm wide) possess excellent superconducting properties with zero resistivity at 89.5 K and critical current densities of above 2 MA/cm2 at 77 K. On the other hand, oxygen‐poor regions are semiconducting and exhibit thermally activated transport, well described by a three‐dimensional, variable‐length hopping process. Their resistance below 100 K is above 10 MΩ/square. A number of test structures patterned by laser writing, such as a microbridge, coplanar transmission line, open‐ended microwave resonator, photoconductive switch, and Y‐Ba‐Cu‐O field‐effect transistor, have been presented.