To go from Mexico City to Guanajuato there are several possibilities (all prices in US $):

• Have a connection with Aeromexico (check with your local travel agency) and fly from Mexico City to Leon. Take a taxi from the airport at Leon to the city of Guanajuato (CIMATEL in La Valenciana). The taxi fare may be around $25.00 (dollars)
• If you are at the airport in Mexico City, go to the Central de Autobuses del Norte and take a (non-stop) bus to Guanajuato. The easiest way to go from the airport to the Central de Autobuses del Norte is by taking a taxi (around $20.00 dollars). Buy a taxi ticket with the authorized service at the booths inside before leaving the customs area. The bus fare from Mexico City to Guanajuato is around $30.00 - $35.00 (dollars), it takes about 3.5 to 4 hrs and the buses are very comfortable, the last bus usually leaves at 21:00 hrs. To obtain further information about the buses schedule, please consult the web page at: ETN . Once you are in the Central de Autobuses in Guanajuato take a taxi to the CIMATEL in La Valenciana. The fare is around $5.00 (dollars).
• If you want to travel and have a car in Guanajuato, you can rent one (almost any license is valid for this purpose). It is very easy to get to Guanajuato (ask for some directions at the car rental office). The roads are quite good and safe.