A companion festival to the Summer in Old Ljubljana Town, the Nights in Old Ljubljana Town has been organised since 1988 by Imago Sloveniae. Its primarily classical music-oriented programme is accompanied with a strong selection of jazz, ethno, chanson, tango, klezmer, and other music of this vein. It also encompasses scientific conferences and lectures on music, literature and poetry readings, social dance gatherings (salsa, tango, swing, etc.), and various happenings for children like puppet theatre shows and workshops.
The festival is traditionally presented in the last week of August. The concerts are held at a dozen different, mostly open-air locations in the old city centre, each of them having a specific programme concept (for example, the stage in front of the City Hall – large ensembles, orchestras, and big bands; Gornji trg – avant-garde jazz, etc.)
The breadth of the festival makes it hard to pin down. Basically, it is forefronts an international selection of contemporary creative endeavours in jazz, chanson, and various takes on traditional musics from all over the world. Its programme is sometimes knit around a concept, like when it focused on accordion in 2012, staging its various applications in a variety of musical forms (this featured Simone Zanchini (IT), Miodrag Spasić (RS), Rhythm & Blues Resistance (HR), Bratko Bibič & The Madleys, Janez Dovč, Jure Tori, and some others).
Other guests of the festival include Barcelona Gipsy Klezmer Orchestra (ES), Tran Quang Haij (VN), Alwan Trio (EG), Lasanthi (LK), Global Culture Nasu (JP), Donauwellenreiter (AT/IT), The Hungarian National Gypsy Orchestra (HU), Bakalina, Uršula Ramoveš in Fantje z Jazbecove grape, Vlado Kreslin, Orlek, Lolita, and numerous others. A part of the line-up is sometimes programmed in collaboration with institutions like Radio Slovenia Third Channel - ARS and Radio Študent (RŠ).
The project also includes literary events, art exhibitions, dance performances, milonga evenings, and different art workshops and round tables, which in the past have been hosted in co-production with the Faculty of Arts, University of Ljubljana, the Folk Slovenia Cultural Society, Radio Študent (RŠ), the Department of Musicology, University of Ljubljana, the Institute of Musicology, the International Council for Traditional Music (ICTM), Slovenia, and a number of others.