It is never too late to invest in mutual funds for retirement. As such, if you plan to invest in some of the best funds, the Zacks Mutual Fund Rank can provide you with valuable guidance.

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.

American Century Fundamental Equity A (AFDAX Quick QuoteAFDAX - Free Report) : 1.04% expense ratio and 0.79% management fee. AFDAX is classified as a Large Cap Blend fund. More often than not, Large Cap Blend mutual funds invest in companies with a market cap of over $10 billion. Buying stakes in bigger companies offer these funds more stability, and are well-suited for investors with a "buy and hold" mindset. AFDAX has achieved five-year annual returns of an astounding 11.03%.

Frost Growth Equity Investor (FACEX Quick QuoteFACEX - Free Report) . Expense ratio: 0.88%. Management fee: 0.5%. FACEX 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. This fund has managed to produce a robust 11.49% over the last five years.

BlackRock Long-Horizon Equity R (MREGX Quick QuoteMREGX - Free Report) is an attractive large-cap allocation. MREGX is a Global - Equity mutual fund. These funds invest in large markets like the U.S., Europe, and Japan, and operate with very few geographical limitations. MREGX has an expense ratio of 1.45%, management fee of 0.8%, and annual returns of 10.87% 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.