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 way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. Using the Zacks Mutual Fund Rank of over 19,000 mutual funds, we've identified three outstanding mutual funds that are ideally suited to help long-term investors pursue and achieve their retirement investing goals.

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

Vanguard Strategic Equity Fund (VSEQX): 0.17% expense ratio and 0.16% management fee. VSEQX is a Mid Cap Blend mutual fund, and usually features a portfolio with stocks of various styles and sizes, allowing for diversification within a strategy that focuses on mid cap companies. VSEQX has achieved five-year annual returns of an astounding 12.84%.

BlackRock Global Small Cap I (MAGCX). Expense ratio: 0.71%. Management fee: 0.66%. MAGCX is a Global - Equity mutual fund, which invests their assets in large markets, leveraging the global economy. This fund has managed to produce a robust 12.74% over the last five years.

Alger 35 Z (ATVPX Quick QuoteATVPX - Free Report) is an attractive large-cap allocation. ATVPX 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. ATVPX has an expense ratio of 0.56%, management fee of 0.45%, and annual returns of 14.45% 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.