Mutants of bacteriophage phi29 DNA polymerase with increased protein stability and increased half-life, compared to wild type DNA polymerase. The disclosed mutants are more stable in reaction mixtures with or without DNA. The inventive phi29 DNA polymerase mutants generate more amplification product. The inventive phi29 DNA polymerase mutants amplify genomic DNA with less bias compared to wild type DNA polymerase. Selected mutations increase the affinity of polymerase for DNA template.