Samples with composition Y1−xGdxBa2Cu3O7 (x=0.001–0.005) are prepared and TC, ΔTC, JC, ρ(300 K) are measured. It is shown that upon substituting yttrium by small amounts of gadolinium, JC can be improved significantly. The anticorrelation of JC with ΔTC and ρ(300 K) is established. The possible role of gadolinium in enhancing JC is discussed. General guidelines for getting high JC values are gathered.