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.

MFS Mass Investors Growth Stock I (MGTIX Quick QuoteMGTIX - Free Report) : 0.46% expense ratio and 0.33% management fee. MGTIX 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. With annual returns of 12.8% over the last five years, this fund is a winner.

JPMorgan US Equity Fund R5 (JUSRX Quick QuoteJUSRX - Free Report) : 0.54% expense ratio and 0.4% management fee. JUSRX 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. JUSRX, with annual returns of 12.48% over the last five years, is a well-diversified fund with a long track record of success.

Fidelity Advisor Technology A (FADTX Quick QuoteFADTX - Free Report) . Expense ratio: 0.98%. Management fee: 0.53%. Five year annual return: 19.05%. FADTX is part of the Sector - Tech mutual fund category that invests in technology and lets investors own a stake in a notoriously volatile sector, but with a much more diversified approach.

We hope that your investment advisor (if you use one) has you invested in one or all of the top-ranked mutual funds we've reviewed. But if that isn't the case, it might be time to have a conversation or reconsider this vitally important relationship.