Patients will participate in two arms of the trial, one in which morphine will be administered transdermally, and, after a 3 day wash out period, one in which morphine will be administered subcutaneously.

Patients will participate in two arms of the trial, one in which morphine will be administered transdermally, and, after a 3 day wash out period, one in which morphine will be administered subcutaneously. Blood draws will be done after both dosing methods in order to compare blood levels of morphine by the different routes.

Inclusion Criteria:

• Chronic cancer pain
• Minimum baseline pain of 3/10
• No change in medications over 3 days prior to study period
• Ability to give informed consent
• Willingness to undergo repeated blood sampling

Exclusion Criteria:

• Use of morphine or codeine in 3 days prior to study
• Known sensitivity to morphine
• Prior anaphylactic reaction to any opioid
• Clinically significant anemia