Thank you all. It now seems to be working. Since I am a total newbie, when I tried to read the manual, I got lost. Your help was valuable. I only have one question left. When I use Serial.print(sensor_reading), and sensor_input=Serial.read() on the transmitting and receiving Arduinos respectively, I only get some values roughly between 40 and 60. Is there a problem with the communication of the two Xbees, or is it that I'm just not reading the data correctly (as I said earlier, I am using Serial.print, not Serial.write). Also, can I just use Serial.read(), and store its value in a variable, or do I need some other kind of processing after that?