In these places you can always find a good jazz concert in town. Močvara offers Jazz concerts twice a month, be sure to check out their website mocvara.com for exact dates and times, and you can also buy tickets online. On Wednesdays, the Sax club offers the New Croatian Jazz concert programme and admission is free. KCM in Kranjčevićeva Street offers jazz sessions, so stop by.
In the Zagreb jazz cycle - Jazz orchestra of HRT at the Museum of Contemporary Art (Avenija Dubrovnik 17) on January 31 - Nenad Vasilić (double bass), March 13 -  Renato Chicco (organ), April 17 - Janko Novoselić (drumss), May 15 - Ted Nash (saxophone), June 12 - Makoto Ozone (piano). You can get tickets for 8 EUR.