I recently returned from Lao with a double entry visa. The first 60 days expires at the end of October. I am under the impression that I can go to the immigration office and get 30 more days at that time. After those 30 days are up I will need to leave the country and upon return I will get 60 more days. This will be at the end of November. My question is I will be leaving for a week during Christmas and I would like to know if I can return on the same visa.

Thank You

No you cannot.

You would need to make your second entry before your visa expires. For a visa issued in Vientianne that would usually be around day 88/89 (end Nov). You would get second 60 day permission to stay on entry. You could then obtain a re-entry permit from immigration to preserve the remaining days on your visa (fee 1,000 baht) on re-entry in December. Note a re-entry permit does not give any more days. With tourist visas free until 31 March 2011 it may be easier option just obtain a new visa.