We examined the efficiency of sedating juvenile steelhead Oncorhynchus mykiss with 12.5, 25, or 50 mg/l clove oil concentration as it would relate to in situ sampling and marking. We compared handling effort and processing time among dosages for fish sedated with clove oil, implanted with a 23-mm passive integrated transponder (PIT) tag, weighed, measured, and fin clipped. In addition, we compared anesthesia induction, recovery, and initial and delayed mortality among dosages for fish sedated with clove oil. Fish reached each anesthesia induction stage faster as clove oil concentration increased. Handling effort was significantly more difficult for individuals anesthetized in the 12.5 mg/l clove oil concentration compared to 25 or 50 mg/l. Handling effort did not differ between fish sedated with 25 or 50 mg/l. Handling time was significantly longer for fish anesthetized with 12.5 or 25 mg/l clove oil concentrations compared to 50 mg/l. Handling time did not differ between fish anesthetized with 12.5 or 25 mg/l. Processed fish (i.e. PIT tagged, weighed, measured, fin clipped) recovered significantly quicker when anesthetized with 12.5 mg/l clove oil concentration followed by 25 and 50 mg/l. Time to each anesthesia recovery stage did not differ between processed fish and controls. We observed no initial post-tagging mortality. Though we observed delayed mortality, it was low and did not significantly differ among clove oil concentrations. Our results support the use of clove oil as a fish anesthetic, and 50 mg/l was an effective concentration when used for PIT tagging juvenile steelhead.