This paper presents GRASS (Graz corpus of Read and Spontaneous Speech), the first large scale speech database for Austrian German with both read and conversational speech. In total, the corpus contains approximately 1900 min of speech in which 38 speakers produced more than 220,000 word tokens from 14,593 different word types. The corpus consists of three components. First, the Conversational Speech Component contains free conversations of one hour length between friends, colleagues, couples, or family members. Second, the Commands Component contains commands and keywords which were either read or elicited by pictures. Third, the Read Speech Component contains phonetically balanced sentences and digits. The speech of all components has been recorded at fullband quality in a soundproof recording-studio with head-mounted microphones, large-diaphragm microphones, a laryngograph, and with a video camera. The corpus was fully annotated at the orthographic level, and partly also at the segmental, sub-segmental and prosodic level. Our analysis of conversational speech characteristics such as overlapping speech, laughter, repetitions, hesitations and the use of colloquial and dialectal words allows us to conclude that the conversational speech material is highly casual in nature. The collected corpus provides conversational material for phoneticians and linguists interested in topics specific for Austrian German (e.g., pronunciation variability, prosody, syntax of spoken Austrian German), and for those studying talk in interaction in general (turn-taking, grounding, entrainment, extra-linguistic factors etc.). Furthermore, it is a valuable resource for speech technologists interested in the development of ASR and dialogue systems for different speaking styles of Austrian German.