Well there are a lot of different sources that give out different dates etc for benzo detection time. Erowid only gives the detection times for Diazepam (valium) and Flunitrazepam (rohypnol). Eworid states that the dectection time for valium single use is 7-10 days and for rohypnol it is 2-4 days. Well valium is a longer acting benzo than rohypnol so this might account for the difference but one might wonder what the detection time for alprazolam (xanax) is. Well there arent any sites that give very accurate information on this. <link no longer active> That site gives a comprehensive chart that compares the half lives of various benzos. If you look at the chart it says that the half life of valium is a long half life, it quotes it at 30-200 hours. Also if you check the half life of rohypnol, it had a medium-long half life which falls between 12 and 40 hours. Alprazolam has a short halflife which it says is 9-20 hours. So lets try to make some conclusions with the information given. Valium is detected in the urine for 7-10 days, rohypnol only 2-4 days. Valium has a much longer halflife than rohypnol which might account for the big gap. So where does Xanax fall??? Not really sure but if Xanax has a shorter halflife than rohypnol could you assume that it is detected in the urine for a shorter amount of time? Everyone interested in this topic should check out the chart. It seems that valium has one of the highest half lives out of any benzodiazepine. Many charts say that benzos can be detected anywhere from 1-42 days. 42 days must be someone taking a long acting benzo that is a chronic user and not very active. Here is another chart with the half lives of various benzos. http://www.mja.com.au/public/mentalhealth/articles/norman/no rbox2.html Notice the differences in the numbers, they are quite large. This chart says the half life of dizepam (valium) is 20-90 hours. It is classified under "long elimination half-life). Alprazolam (xanax) is classified under "intermediate elimination half-life" and it gives the numbers 6-20 hours. Finally, Flunitrazepam (rohypnol) is also under the "intermediate elimination half-life" benzos and it's half life is 20-30 hours. So if you take all the information from the web and from these charts you can come up with the following statment, which I cannot determine the accuracy of. The half-life of Valium (Dizepam)is longer than the half-life of rohypnol (Flunitrazepam), which is longer than the half-life of xanax (alprazolam). Erowid says valium is detected in the urine for 7-10 days and that rohypnol is detected 2-4 days. Can one assume that xanax would be 2-4 days, maybe less? Since benzos are stored in fat cells it is probably all dependent on how your body is. The amount of fat in your body, your metabolism, your fluid intake and also your activity. Some benzos have a much longer half life than others, and it seems that Dizepam (valium) has one of the longest half lifes of any benzo which probably accounts for the long detection time in urine. Also, valium is a much weaker benzo thus the daily doses much higher. It would not be uncommon for someone to take 80 mg of valium a day but 80mg xanax a day is getting a bit on the EXTREME side. I have came up with this information via the web from many different sites after searching quite a bit. Hope this information will help some of you. I have a few questions though. Does anyone have experience with xanax and drug tests. I took a test the other day and took a 2mg bar of xanax 9 days before. I was working every day being pretty active so hopefully it does not show up. There are so many different sources on the web with different quotes on half life and detection time it is hard to get reliable information. Erowid comes up a big short in the drug testing department when it comes to benzos. If I am reasoning properly his assumptions about the halflives and detection times should be half-accurate . If anyone has experience with benzos and detection time please share your experiences. SWIM just wants to know if 2mg of xanax will show up 9 days after use. If the detection time for valium is 7-10 days and xanax has a much shorter half life then I should be fine. Here is another chart for anyone interested http://www.benzo.org.uk/bzequiv.htm Again this chart shows a much higer halflife for valium (20-100 hours) an a shorter half life for xanax (6-12 hours) so I am proposing that the detection time of xanax is about the same as with rohypnol, maybe even shorter. Remember though everyone is different and everyone's body works differently. Anyone with any information about benzos and drug tests please post there. There is a lot of good information here I just wanted others to be able to quickly view this information and try to help others and maybe us my can come to a conclusion about all this!