This paper considers the 2-adic complexity of Ding-Helleseth generalized cyclotomic sequences of order 2 and period pq, where p and q are distinct odd primes with gcd(p - 1, q - 1) = 2, p - q - 3 (mod 4). These sequences have been proved to possess good linear complexity. Our results show that the 2-adic complexity of these sequences is at least pq - q - 1. Then it is large enough to resist the attack of the rational approximation algorithm.