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 learn about some of Zacks' highest ranked mutual funds with low fees you may want to consider.

If you are looking to diversify your portfolio, consider Bridgeway Small Cap Value N (BRSVX Quick QuoteBRSVX - Free Report) . BRSVX is a Small Cap Value mutual fund option, which typically invest in companies with market caps under $2 billion. This fund is a winner, boasting an expense ratio of 0.83%, management fee of 0.61%, and a five-year annualized return track record of 14.62%.

Dreyfus Appreciation Fund Y (DGYGX Quick QuoteDGYGX - Free Report) is a stand out amongst its peers. DGYGX 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 five-year annualized performance of 10.71%, expense ratio of 0.59% and management fee of 0.55%, this diversified fund is an attractive buy with a strong history of performance.

JPMorgan Large Cap Growth R2 (JLGZX Quick QuoteJLGZX - Free Report) is an attractive large-cap allocation. JLGZX is a Large Cap Growth mutual fund, and these funds invest in many large U.S. firms that are projected to grow at a faster rate than their large-cap peers. JLGZX has an expense ratio of 1.19%, management fee of 0.45%, and annual returns of 12.42% over the past five years.

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.