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.

AB Value I (ABVIX Quick QuoteABVIX - Free Report) : 0.7% expense ratio and 0.55% management fee. ABVIX is a Large Cap Value mutual fund, which invests in stocks with a market cap of $10 billion of more, but whose share prices do not reflect their intrinsic value. With annual returns of 11.53% over the last five years, this fund is a winner.

Fidelity Advisor Series Small Cap (FSSFX Quick QuoteFSSFX - Free Report) is a stand out amongst its peers. FSSFX is a Small Cap Blend mutual fund, allowing investors a way to diversify their funds among various types of small-cap stocks. With five-year annualized performance of 13.07%, expense ratio of 0.01% and management fee of 0%, this diversified fund is an attractive buy with a strong history of performance.

T. Rowe Price Mid-Cap Growth Fund (RPMGX Quick QuoteRPMGX - Free Report) is an attractive large-cap allocation. RPMGX is a Mid Cap Growth mutual fund. These funds aim to target companies with a market capitalization between $2 billion and $10 billion that are also expected to exhibit more extensive growth opportunities for investors than their peers. RPMGX has an expense ratio of 0.76%, management fee of 0.61%, and annual returns of 10.29% over the past five years.

There you have it. If your financial advisor had you put your money into any of our top-ranked funds, then they've got you covered. If not, you may need to talk.