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.

Here are the funds that have achieved the Zacks Mutual Fund Rank #1 (Strong Buy) and have low fees.

If you are looking to diversify your portfolio, consider Invesco Comstock R (ACSRX Quick QuoteACSRX - Free Report) . ACSRX 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. This fund is a winner, boasting an expense ratio of 1.05%, management fee of 0.38%, and a five-year annualized return track record of 12.55%.

Goldman Sachs Large Cap Growth Insights R (GLCRX Quick QuoteGLCRX - Free Report) . Expense ratio: 1.21%. Management fee: 0.52%. GLCRX 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 15.4% over the last five years.

AQR Small Cap Multi-Style R6 (QSERX Quick QuoteQSERX - Free Report) is an attractive large-cap allocation. QSERX is a Small Cap Blend mutual fund, and usually targets stocks with market caps of less than $2 billion, letting investors diversify their funds among other kinds of small-cap equities. QSERX has an expense ratio of 0.5%, management fee of 0.45%, and annual returns of 11.51% 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.