You can file the I-485 simultaneously with the immigrant petition (I-130 or I-140) or once the I-130 or I-140 receipt notice has arrived from the USCIS, as long as a visa number is immediately available.The priority date determines visa availability. For relative petitions, the priority date is the date the I-130 immigrant petition was properly filed. For employment-based petitions, the priority date is the date the labor certification was filed with the Department of Labor (DOL) or the date the I-140 immigrant petition was filed with the USCIS if no labor certification was required. The priority date becomes "current" when there is a visa available. If the priority date is current, you may file for Adjustment of Status during the month when the priority date is current. The State Department issues a document each month called the Visa Bulletin that lists the current priority dates for each immigrant preference category. There are also special situations, such as the diversity visa lottery, registry, and asylum that permit filing for adjustment of status within specified timeframes.