Does 2003 Honda Civic DX 4DR has timing belt? If Yes when to replace it?

Factory reccomendation is 110000 mi. change the water pump timing belt and tensioner...

For the 2003 Honda Civic:
Yes it does!
Officially (per Honda) 5-years or 90,000 miles.

Click on the following free, direct Link. It has the Timing Belt and Mark(s) Diagrams you will need if you do it yourself. It has several other Diagrams that will be helpful in your endeavors.

Let me know if this helped.....

http://www.2carpros.com/car_repair_information/year/2003/make/honda/model/civic/2003_honda_civic_timing_belt_diagram_marks.htm

Yes and 80,000 miles and change the water pump the same time too

Yes it does it should be replaced every 60,000 miles. Thanks for using Fix ya