Investing in mutual funds for retirement is never too late. And the Zacks Mutual Fund Rank can be an excellent tool for investors looking to invest in the best funds.

The easiest, most reliable way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. The Zacks Mutual Fund Rank, which covers over 19,000 mutual funds, has helped us identify three outstanding options that are perfect for any long-term investors' portfolios that is retirement-focused.

Let's take a look at some of our top-ranked mutual funds with the lowest fees.

Goldman Sachs Blue Chip US Equity A (GAGVX Quick QuoteGAGVX - Free Report) : 1.04% expense ratio and 0.55% management fee. GAGVX is a Large Cap Blend fund, targeting companies with market caps of over $10 billion. These funds offer investors a stability, and are perfect for people with a "buy and hold" mindset. With annual returns of 11.55% over the last five years, this fund is a winner.

Janus Henderson Research Institutional (JAGRX Quick QuoteJAGRX - Free Report) : 0.56% expense ratio and 0.47% management fee. JAGRX is a Large Cap Growth option; these mutual funds purchase stakes in numerous large U.S. companies that are expected to develop and grow at a faster rate than other large-cap stocks. JAGRX, with annual returns of 12.6% over the last five years, is a well-diversified fund with a long track record of success.

Fidelity Select Technology (FSPTX Quick QuoteFSPTX - Free Report) : 0.69% expense ratio and 0.53% management fee. FSPTX is a Sector - Tech mutual fund, allowing investors to own a stake in a notoriously volatile sector with a much more diversified approach. With a five-year annual return of 18.89%, this fund is a well-diversified fund with a long track record of success.

These examples highlight the fact that there are some astonishingly good mutual funds out there. If your advisor has you in the good ones, bravo! If not, you may need to have a talk.