There is no limit to the number of reward credit cards you can have, although in terms of managing your personal finances you do not want to have too many cards to have to pay off each month.
While different credit cards give different rewards, it is better to pick the right reward credit card for you, rather than having lots of credit cards. This is because you will have the temptation to overspend, and because lenders may be wary of you if you have applied for a lot of potential credit.
Having lots of credit cards, whether you use them or not, can affect your credit rating, and whether you are approved for credit such as a loan, mortgage or mobile phone or broadband contract. Find out more about How to check your credit rating.