I have a misdemeanor on my record for possession of marijuana.

Dear Martin,   In order to answer your question fully, I would need to know the particulars of your situation.  First I would need to knowwhat your immigration status is.  I would need to know your entire criminal record, including any dismissed charges, and I would need to know all the details of your marijuana conviction.  The law you would be dealing upon returining to the US is the law on admissibility.  Conviction (or admitting the elements) of a drug crime, among others, can make a person inadmissible.  However, there is a waiver where the alien is requesting a waiver of only one such offense, where the drug is marijuana only, and the amount is 30 grams or less for personal use.  I  think you would be well advised to have your case looked at carefully before you depart the US.  If you want to consult on this matter with our office we can schedule a telephonic or in person consultation by calling (619) 291-1112. Best regards, Jan Joseph Bejar, Esq.