This paper presents a fast split-radix-(2×2)/(8×8) algorithm for computing the two-dimensional (2-D) discrete Hartley transform (DHT) of length N×N with N = q*2m, where q is an odd integer. The proposed algorithm decomposes an N×N DHT into one N/2×N/2 DHT and forty-eight N/8×N/8 DHTs. It achieves an efficient reduction on the number of arithmetic operations, data transfers and twiddle factors compared to the split-radix-(2×2)/(4×4) algorithm. Moreover, the characteristic of expression in simple matrices leads to an easy implementation of the algorithm. If implementing the above two algorithms with fully parallel structure in hardware, it seems that the proposed algorithm can decrease the area complexity compared to the split-radix-(2×2)/(4×4) algorithm, but requires a little more time complexity. An application of the proposed algorithm to 2-D medical image compression is also provided.