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.

Champlain Mid Cap Fund Advisor (CIPMX Quick QuoteCIPMX - Free Report) : 1.09% expense ratio and 0.7% management fee. CIPMX 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. With annual returns of 7.53% over the last five years, this fund is a winner.

Deutsche Capital Growth Institutional (SDGTX Quick QuoteSDGTX - Free Report) : 0.71% expense ratio and 0.46% management fee. SDGTX 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 yearly returns of 13.8% over the last five years, SDGTX is an effectively diversified fund with a long reputation of solidly positive performance.

JPMorgan US Equity Fund R5 (JUSRX Quick QuoteJUSRX - Free Report) . Expense ratio: 0.54%. Management fee: 0.4%. Five year annual return: 14.79%. JUSRX is part of the Large Cap Blend section, and these mutual funds most often invest in firms with a market capitalization of $10 billion or more. By investing in bigger companies, these funds offer more stability, and are often well-suited for investors with a "buy and hold" mindset.

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.