Laryngeal activity in the production of voiceless obstruents and obstruent clusters in Icelandicwas investigated by the combined techniques of transillumination and fiberoptic filming of the larynx. Contrasts of preaspirated, unaspirated, and postaspirated voiceless stops were found to be produced basically by differences in laryngeal-oral timing. In clusters of voiceless obstruents, one or more continuous laryngeal opening and closing gestures occurred depending on the segments in the cluster.Peak velocity of glottal abduction was higher for fricatives than for stops. This, and other differences in laryngeal adjustments and interarticulator timing between stops and fricatives, are most likely due to different aerodynamic requirements for stop and fricative production. The present results further question the usefulness of timeless feature descriptions for modeling speech production.