The article presents requirements of currently valid standards concerning ultrasonic tests of welded joints with reference to PN-EN ISO 17635:2010, PN-EN ISO 16810:2014, PN-EN ISO 16811:2014 and PN-EN ISO 17640:2011. The article discusses principles governing the selection of ultrasonic probes, a manner of determining allowances for transfer losses and a manner helping adjust an appropriate test level. In addition, the article characterises techniques applied when setting a reference level as well as analyses positions of probes and a number of beam insertion angles when testing butt joints at various testing levels.